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Intel is changing the future of power supplies with its ATX12VO spec

154 points by wyldfire 7y ago

deleted 7y ago
[deleted]
raverbashing 7y ago
It's an interesting development. Things like -12V made sense on the 80s (sigh), while high-powered 3.3v/5v needs made sense on the 90s (it still makes some sense today, for example for USB) Though one thing they might have considered but maybe rejected was going for a higher voltage single rail power supply (something like 24v) Your board might still need those voltages but will have to DC-DC convert it themselves (as opposed to a multi-tap transformer as the article was implying)
- throwaway2048 7y ago
  pretty much all modern boards use DC/DC power stages from 12v, even for 5v and 3.3v stuff.
  - baybal2 7y ago
    Indeed, found that for myself when got into mobo design. ATX 5V is really unsuitable for USB power, and can play tricks on you. Similarly, 3.3V from PSU is useless at powering 3.3V logic. You have to do power staging on board to guarantee that PCI and i2c stuff turns on after the bridge/soc. Some PSUs don't follow reset timings, or don't do them at all on standby rail. So if you do ATX power by the book, you may end up with improperly inited board, and 3.3V ICs booting up before the CPU. So, yes, most of ATX power supply functionality is already duplicated by most mobos
    - mmastrac 7y ago
      > ATX 5V is really unsuitable for USB power, and can play tricks on you. Would you mind elaborating on this?
      - baybal2 7y ago
        Poor transient response. Ringing on some PSUs. Out of spec ripple on most PSUs.
    - garaetjjte 7y ago
      >ATX 5V is really unsuitable for USB power, and can play tricks on you. Why? I don't think current motherboard duplicate 5V converter. >you may end up with improperly inited board, and 3.3V ICs booting up before the CPU. Why it cannot just hold reset line for these chips high until CPU started?
      - Gibbon1 7y ago
        A lot of peripheral IC's don't have reset lines. Sometimes this is a big big problem. You can end up with failure to come up maybe 1 in 10,000. Exactly the sort of thing that shows up late in development or worse in the field. Tip: If anyone tells you power supply and reset sequencing is 'easy' ignore them.
      - dezgeg 7y ago
        Holding chips in reset is not the only thing that matters. Complex chips may have power-sequencing restrictions; for example 1.8V power rail might need to be up before 3.3V, otherwise the chip gets damaged.
    - chungus_khan 7y ago
      Yeah, unfortunately we've thoroughly decayed past the good old AT days of being able to power logic straight off of the 5V. It helped that in those days there was one IBM making the PCs.
londons_explore 7y ago
Why does this still have 10 pins? 2 pins would be plenty. 12v Power, Ground, and an overlaid capacitively coupled 2 way data comms running at a few hundred khz to send and receive status messages, fan speeds, model/serial numbers, firmware/ temperatures, on/off commands, etc.
- generatorguy 7y ago
  to deliver 1500 watts at 12v through one pin would be 125 amps. 5 pins each with 25A I would think you’d want at least 14 gauge per pin and even then I think they would be rather warm.
  - sjwright 7y ago
    If you’re sending 1500 watts directly into a motherboard, something is probably wrong. Massive power draws (CPU, GPU) would always get their own direct connection, just as they do today. Apply this simple rule of thumb: watts become heat. The only major exception to this is where the power has exited the computer via USB or similar.
    - jmgao 7y ago
      PCIe specifies that you can get 75W from the connector, which adds up quickly.
    - generatorguy 7y ago
      I haven't assembled a PC since the pentium 200 days. I recall hard drives, floppy drives, and the motherboard had their own power connections but not the CPU or GPU of the time. Still a single pin is probably something like a #18 gauge and would only be good for 10A before it gets too warm for comfort.
      - x0 7y ago
        I always thought that was why the big ATX connector has multiple 12V wires, multiple GND wires, etc. To push heaps of current, but using a normal gauge of wire, rather than something huge.
Melkman 7y ago
I wonder how easy this would make server local UPS systems. A battery with a single buck/boost converter should be enough as a power supply. Just need to add a mains fed charge circuit.
- mmastrac 7y ago
  Probably would allow very cheap power supplies w/built-in UPSes. 12V±5% voltage is the allowed range.
  - baybal2 7y ago
    ±5% would not be that easy with current spikes from CPU and GPU. It's 300W-400W load going to near zero and back within microseconds.
    - chmod775 7y ago
      It's not black magic to handle that with a capacitor or two.
      - baybal2 7y ago
        It is, first the cap needs to ve huve enough, second ESR will need to be very, very low unless you want to cool the cap as well
  - michaelt 7y ago
    Most desktop users would probably prefer a UPS that also ensured their monitor stayed on.
    - loeg 7y ago
      I actually leave my monitor off UPS intentionally. While I'm away, I'd rather my workstation survive a brownout or short loss of power and if I'm actively working, it's easy enough to move the monitor's power cable to the UPS to save my work and shut down. My CPU draws ~45W at idle; my monitor draws a whopping 130W — having it on battery materially shortens the off-AC runtime.
mmastrac 7y ago
12V makes so much more sense to be sending around - the losses at lower voltages are rough. It would be nice to replace legacy molex connectors with a more modern standard, however.
- kbumsik 7y ago
  > It would be nice to replace legacy molex connectors with a more modern standard Any example of the modern one? I personally have no issues with the current one. I am not sure if those molex connectors should be called as legacy.
  - wlesieutre 7y ago
    Bulkiness is my main complaint, they can be a real nuisance in small form factor cases.
    - usrusr 7y ago
      And some recent examples are a terrible fit, I remember them aligning much smoother. A clear sign that manufacturers consider them second class. And nobody will complain, because it just strengthens the pre-existing assumption that the new plugs are better.
    - willis936 7y ago
      Industrial design demands this. A replacement connector should be difficult to remove and use sufficiently thick cables. Because of the requirements there is little room for improvement and thus we have used the same connectors for 30 years.
      - wlesieutre 7y ago
        The molex 2.36mm pins can apparently carry 8.5A, which at 12V gives you about 100W. That’s useful for some power hungry components, but I wish there were a smaller alternate 4-pin power cable standard that I could use to route power around to things like fans and SATA SSDs. Something in between the giant molex connectors and a 3-pin fan connector.
superkuh 7y ago
This makes sense for specific use case computers, specialty ones, etc. So it'll be adopted. And because of economies of scale it'll push into actual desktop computers and their mobos. Having to dissipate all that heat on/in the mobo will be terrible for actual desktop computers. But it'll happen anyway because it's better for corporations and the desktop market doesn't drive their decisions.
- deleted 7y ago
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- baybal2 7y ago
  You already dissipate quite a lot in CPU VRMs. For everything 3.3V on mobo, a linear reg on board will still be more efficient than one in the PSU.
  - superkuh 7y ago
    And the VRMs and associated circuitry are the most likely thing to die on the motherboard. The PSU, at least in my experience, is the most likely thing to die in a desktop computer. So now you have all the most likely to die components on the most expensive part of your desktop system. Being able to replace the PSU without the cost of the mobo is great for human people. For corporate people and their economies of scale it makes less sense than just making everything 1 thing and throwing it out when it breaks.
- jleahy 7y ago
  A typical CPU (or SSD even) uses a voltage of 0.9V currently, surely it doesn't matter whether the motherboard is converting 12V to 0.9V or 5V to 0.9V. Back when this stuff was originally designed 12V, 5V and 3.3V was all you needed (actually with the AT standard it was just 12V for motors and 5V for logic, that was pre-CMOS). Now every component requires a different voltage (if there's any standard it might be 1.8V or 1.2V), and to get several hundreds watts of power at 0.9V would require cables about an inch thick. 12V is the defacto standard for powering pretty much anything these days. Converting 12V into whatever you want is utterly trivial and incredibly efficient.
DiabloD3 7y ago
Four important things to consider: First, this already happened to some extent. Outside of drives and fans, the virtually all of the power used in your system is exclusively 12v; either from the 12v pins on your ATX24 or P4 or EPS12 connectors, or via the PCI-E connectors; very little non-drive or non-fan power is supplied via 3.3 or 5v rails. Second, almost all PSUs today use 12v DC to 3.3/5v DC converters to increase efficiency given how little 3.3v and 5v is required. The PSU itself is often designed internally as a high efficiency multi-module single rail 12v-only design. Third, Intel is not in a position to dictate anything. Intel has tried to float many changes in the standards (such as the WTX board standard (with matching incompatible mobo plug), and the BTX board standard (using ATX plugs)), and all failed. The only thing that stuck was using 4 and 8 pin PC Minifit Jr plugs (the same ones ATX, PCI-E and countless other plugs come from); and, annoyingly, somehow not compatible with PCI-E's pinout. Fourth, Intel is also not the dominant player in the field now, AMD is. They failed to get major changes through as the dominant player, what makes them think anyone cares to hear what they have to say today? It is unlikely AMD will ever ship machines that don't ship with normal ATX unless they just jettison the ATX24 altogether. Side note: 12v capacity: ATX24 144w, P4 192w, EPS12 336w, PCI-E 6 75w, PCI-E 8 150w, and the PCI-E slot itself 75w. A modern desktop could theoretically be ran off a dual EPS12 and a PCI-E 8+8 for the GPU; modern mobo designs run the CPU and RAM VRMs off the EPS12 entirely, modern GPU designs run the GPU VRMs off of PCI-E plugs and the VRAM VRMs off the PCI-E slot power, very little power of any voltage is supplied to the system via ATX24. Another side note: Any board that has a legitimately clean 5v rail for USB is not feeding it off the PSU directly. Any board that has absolutely garbage USB power probably committed this sin.
- tedunangst 7y ago
  Not sure I would classify AMD as the dominant player in the field just yet.
- sp332 7y ago
  Yeah, this is just rearranging some things to avoid California's new efficiency regulations. If you move the inefficent stuff to the motherboard, the PSU magically gets more efficient!
tus88 7y ago
Fuck them. Building retro PCs using modern power supplies will get ever more harder now.
- sounds 7y ago
  It'll be easy to find converters once the market shifts. There are enough retro builders that one will get built.
Animats 7y ago
Makes sense. Should have happened long ago. All those old voltages date from when +5 from the power supply was used directly by the logic. Facebook's Open Compute rack delivers only +12 to the boards and drives, and that's from 2011. There's a power supply in the base of the rack that takes in three-phase AC or 48 VDC or whatever and puts out +12VDC. All other conversion is on the board. This is just catching up desktops to where the data center went years ago.
- jabl 7y ago
  I recall Google mentioned something similar in some old explanation about their server designs.
  - m463 7y ago
    I remember reading about that too -- they even put batteries on the motherboard to serve as distributed UPS systems.
- laurencerowe 7y ago
  I believe the Open Compute designs moved to 48 VDC for efficiency.
  - Animats 7y ago
    Ah, they did.[1] The power busbars are in the same place, so you can't have both 12V and 48V in the same rack. The connectors are intentionally incompatible so you can't plug into the wrong voltage. [1] http://files.opencompute.org/oc/public.php?service=files&t=827d028fc82b4b55315a4d7815b43c78 http://files.opencompute.org/oc/public.php?service=files&t=8...
microcolonel 7y ago
So I guess this makes it cheaper to make lower-idling power supplies; or does a high quality current ATX PSU, like one of the Seasonic Titanium models, not meet the CEC standards for idle power?
yellowapple 7y ago
> PSU vendors don’t want to release ATX12VO products for DIY builders until there are motherboards that support ATX12VO. Motherboard vendors don’t want to create products until power supply makers support them. Seems like that could be addressed with one of two adapters: - A passive adapter cable with a female ATX connector (with the 3.3V and 5V pins disconnected) and male ATX12VO connector - An active adapter cable/board with a female ATX12VO connector, the necessary circuits to step voltages down to 3.3V and 5V, and a male ATX connector. One or both of these could happen today and immediately solve that chicken-and-egg problem for the custom market, no?
- Jaruzel 7y ago
  > An active adapter cable/board with a female ATX12VO connector, the necessary circuits to step voltages down to 3.3V and 5V, and a male ATX connector. I think this will definitely happen, as supplies of classic ATX PSUs start to dry up, and people need to keep powering their old machines. This situation already exists for old AT style vintage machines, being powered by ATX PSUs.
- o_x 7y ago
  This is already somewhat happening, but it's very niche: https://j-hackcompany.com/?product=j-hack-m2427-for-corsair-sf-series https://j-hackcompany.com/?product=j-hack-m2427-for-corsair-... https://smallformfactor.net/forum/threads/m2427-cable-management-freedom.10349/ https://smallformfactor.net/forum/threads/m2427-cable-manage...
vifya 7y ago
It was bound to happen eventually, there has been a long trend towards point-of-use regulation displacing multiple output supplies. I'm just surprised they went with 12V, and not 19V which has lower rectification losses, less power loss to wire/trace resistance, and a large existing design ecosystem from laptops where 19V has been the norm for years.
- jacob019 7y ago
  Or 24V or 36V, but alas 12V is the existing standard for legacy reasons so it's the path of least resistance for an overhaul of the PSU spec.
  - deleted 7y ago
    [deleted]
  - dev_tty01 7y ago
    "path of least resistance" -- Ha, I see what you did there.
- thehobgoblin 7y ago
  To me it seems like the ATX12VO specification is more of an endorsement of the direction PC power supplies seem to be moving in rather than a from-scratch redesign. It would be nice to have higher voltage (19V, 24V or perhaps higher) for a single voltage supply, but it would be a far bigger change to the overall PC ecosystem.
  - deleted 7y ago
    [deleted]
- numpad0 7y ago
  Why is it 19V for laptops? I had suspected it’s to compensate for voltage drop at linear regulators. Batteries are either 11.1(3.7v 4 cells) or 14.8(3.7v 3 cells 1-3 parallel) and these voltages doesn’t seem immediately consistent with ATX12V to me.
PaulDavisThe1st 7y ago
I love computers with 12VDC native power jacks. Why? My solar-powered van (interior only, the engine is still diesel) is 12VDC everywhere, and that's good clean battery DC, not some noisy-ass AC/DC conversion. I love it so much that 2 of the last 3 computers I built (on an ATX form factor) were 12VDC native. I have external AC/DC power supplies for them, but when travelling/living in a solar-powered environment, I get to just plug them straight into the clean juice. Sadly, monitors used to be this way too - they came with external power bricks and were 12VDC native. But sometime in the mid-2000's, something changed. My guess is that someone figured out how to shrink the necessary converters to a size that made it more "sensible" to put them inside the monitor. Result: almost impossible now to find a monitor you connect to a 12VDC supply. The one I have in the van took me months to find on ebay back in 2015. The only exception are "TV" monitors specifically made for RVs, which is great and all, except that most of them are crap compared to a modern monitor. One small problem with plugging 12VDC native computers into a solar system: it's not atypical for the solar charge controller to drive the charge voltage over 14V, at which point most internal "PSUs" designed for 12V will shutdown. You need a voltage regulator between you and the battery-terminal voltage.
- whoopdedo 7y ago
  My 4k Monoprice monitor is 12V. So it's not as impossible as you think.
- jniedrauer 7y ago
  Do you find that it's more power efficient to run a custom built machine like that? I would think that using a laptop as your daily driver would stretch your battery bank further, since it's designed from the ground up for battery power. I lived off solar power for a while, and that was my thinking. I never did the math to verify it though.
  - PaulDavisThe1st 7y ago
    I haven't done any measurements. What I will say is that the machine I used to use in the van lost its video output (the perils of onboard graphics), and I've found it impossible to source a reasonable replacement mobo. As a result, I've switched back to using a laptop (lenovo Y700) in the van. What I notice as a potential improvement is that it effectively lets me store an extra X hours of power for computing, because I'm adding the laptop battery to the overall storage. Compared to my "house batteries", the laptop batteries are of course very small. But getting (say) 3 hours of work time stored up in the laptop does seem like a plus, especially on cloudier days.
ksec 7y ago
I actually want a spec that is similar to Apple's Mac Pro, there should be Zero Cables.
ChuckMcM 7y ago
I remember the days when Microsoft and Intel would host the "PCxx" spec (where xx was the last two digits of the year) and tell everyone what all the standards for desktop machines were going to be for the next few years. Those days are gone though. 12V rail PSUs are nice for a number of reasons but I always liked that you could feed your DC input from the AC side or a battery and have a "free" UPS at the same time. It is a bit tricky with a switching supply since you don't want to have the battery seeing 25Khz power outages as the switcher turns on and off but its very doable. With a little bit of instrumentation you could have the PC itself control charging and monitoring the battery itself so only a minimal amount of hardware needed to give every motherboard its own UPS.
- effie 7y ago
  I am very much interested in this, using DC power sources is the future. How do I go around adding a 12V DC power supply to the ordinary ATX computer? Can you find some links for this?
  - ChuckMcM 7y ago
    Such supplies exist for some levels of power. Very popular in the MiniITX community where power levels are < 300W.[1]. There is also a wealth of material on developing DC to DC converters and a number of modules for the same. For a non-engineer putting something together I would look at DC-DC converter modules (see https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=dc%20to%20dc%20converter https://www.digikey.com/products/en/power-supplies-board-mou...) that provided the necessary power rails, at the power level that was required. Such a solution would not be compact and integrated like one that was designed from scratch to be used in this way, but would certainly work. I used one of the MiniITX supplies to power a system that is mounted in a box on a tree with a solar panel charging a deep cycle battery. It is the download/storage point for a number of wildlife cameras nearby. [1] https://www.amazon.com/250w-DC-ATX-Power-Supply-Supplies/dp/B00NB6U3TS https://www.amazon.com/250w-DC-ATX-Power-Supply-Supplies/dp/...
    - effie 7y ago
gggmaster 7y ago
This will make motherboards more expensive and fragile. Desktop chipsets from Intel can only support two generations of processors. While a good PSU can have ten years of warranty.
- guerrilla 7y ago
  A plan for planned obsolescence?
  - gggmaster 7y ago
    Delivering only 12V has its own pros, so I will give them the benefit of doubt. But I think this move will increase my cost of building desktops.
russdill 7y ago
In one sense this feels like pushing the efficiency problem under the rug. There's a requirement for power supplies to meet a certain efficiency standard, and generating 3.3v and 5v rails are pushing that number down. Solution? Move that task to the motherboard where they won't count against the power supply efficiency requirement. Of course, from a purely engineering perspective, it really does make sense and it's overdue.
- simias 7y ago
  The motherboard "knows more" than the PSU though, it should be able to better deal with these idle power situations by shutting down things that aren't used anymore and powering them back up when needed. An external PSU would have tighter constraints regarding power availability and wouldn't be able to optimize the power profile quite as aggressively since they don't really know exactly what they're driving.
  - russdill 7y ago
    Many DC-DC supplies have auto-standby/idle modes that take care of this problem in an automatic way.
- Faaak 7y ago
  Exactly. I'm pretty sure that once the DC-DC converters are mainly placed in the motherboard, they won't be audited for efficiency anymore and global efficiency will plummet. A shame
  - undersuit 7y ago
    Decreasing efficiency of the motherboard would mean it needs more power, meaning they would require larger power supplies in addition to being a new specification.
    - detaro 7y ago
      Decreasing efficiency of their platform is also not really something Intel has an interest in, since it makes them look bad.
jaclaz 7y ago
Only as anecdata, in my practical experience over the years, I needed to change many power supplies[1], and very few motherboards. (excluding replacements due to upgrades) I would go a little bit further and say that the PSU is probably the most replaced "standard" part of a PC, followed by hard disks. I also a couple times repaired a PSU replacing this or that failed component, but it is simply not worth the time and money, as spare new PSU's are cheap enough, the replacing is very easy whilst even procuring a single chip or capacitor is complex for non-professionals, besides the soldering tools, etc. Hopefully the parts that age or however tend to fail will remain in the (easily replaceable) PSU, otherwise we will see an increase in replaced motherboards. Some sort of (standard) "daughterboard" with the voltage regulating components would have made more sense (to me), but surely it makes less sense from an industrial manudacturing point of view. [1] be it due to capacitors, power transistors or mosfets or whatever, and due to whatever reasons, be it aging, power surges, etc.
- unlinked_dll 7y ago
  Are you buying bottom of the barrel PSUs? I've had the same Corsair unit in three machines over the last decade. Works perfectly fine.
  - aliswe 7y ago
    Might be the power grid.
  - jaclaz 7y ago
    >Are you buying bottom of the barrel PSUs? If you mean that "standard" OEM PSU's (think Asus, Fujitsu, IBM/Lenovo and a few - mini-ITX Shuttle cases) are "bottom of the barrel", yes. Then, since often an used, original, non-standard (say) IBM/Lenovo PSU can be found for a mere 100-150 € on e-bay, I started getting el-cheapo (though not el-cheapest) ones with no appreciable decrease (or increase) in durability, putting them externally and re-mapping the cables. For the mini-ITX cases (that use a not-very-common form factor) I gutted new 1U server PSU's and managed to fit them in. The PC I am writing this with (ASUS) is 2008 and I replaced a PSU in 2012 and one in 2016 or 2017, cannot remember. Out of the four IBM/Lenovo's I have at another office, dated 2010 or 2011, two have still their original PSU, two have the external adapted ATX, no other parts replaced. All in all (and for whatever reasons) I would estimate that over a 5-10 years lifetime of a system[1] there are: 1-2 replacement of PSU's 1 replacement of hard disk(s) No replacement of other parts, let alone the motherboard. Sice 2012 I am at the third Fujitsu ThinClient (used as router) with PSU failing (in this case they are so cheap second hand that I change the whole little machine). [1] the mini-ITX's (there were three of them) before being decommissioned) lasted 2003-2018, i.e. 15 years, running NT 4.0 or 2K 24/7 each with 2 PSU replacements, the last one, being a server grade PSU most probably would be just fine for another five or more years.
rb808 7y ago
Why 12v though? What requires that much voltage? The chips are running at a few volts. Spinning drives are gone, is it just for fans? Seems silly to provide 12v then shift it down again.
- belval 7y ago
  While I don't know the exact component that needs 12V, you have to keep in mind that your typical computer draws about 300W under a small load. 300W/12V means 25 amps. Reduce the voltage without lowering the power consumption and you need bigger wires to handle the increase in amps.
- mcv 7y ago
  True, but motherboards need to shift down anyway. The motherboard controls the voltage of the CPU, and that can be anything.
jotm 7y ago
Not the first time Intel is pushing for tighter VRM integration. Haswell had FIVR, which I think was pretty revolutionary, the die itself contained VRMs for the CPU, IGP, memory and more. Sadly, they gave up on it, probably because it made the processors run hot as hell. There's not enough die area to cool all of that plus the processing cores and multiple controllers themselves
AncientTree 7y ago
The big advantage could be finally moving the PSU out of the case, and having it as just an external power brick. This will make systems significantly lighter and smaller (and thus more portable), take heat out of the case, and improve airflow. You can already buy 330w laptop chargers - just beef them up and you could easily run a mid-grade gaming PC. https://www.amazon.com/Dell-Adapter-DA330PM111-ADP-330AB-332-1432/dp/B00CGA5JQM/ref=sr_1_6?keywords=330w+laptop+charger&qid=1583854491&sr=8-6 https://www.amazon.com/Dell-Adapter-DA330PM111-ADP-330AB-332... You can already buy

154 points by wyldfire 7y ago

deleted 7y ago

[deleted]

It's an interesting development. Things like -12V made sense on the 80s (sigh), while high-powered 3.3v/5v needs made sense on the 90s (it still makes some sense today, for example for USB) Though one thing they might have considered but maybe rejected was going for a higher voltage single rail power supply (something like 24v) Your board might still need those voltages but will have to DC-DC convert it themselves (as opposed to a multi-tap transformer as the article was implying)

throwaway2048 7y ago
pretty much all modern boards use DC/DC power stages from 12v, even for 5v and 3.3v stuff.
- baybal2 7y ago
  Indeed, found that for myself when got into mobo design. ATX 5V is really unsuitable for USB power, and can play tricks on you. Similarly, 3.3V from PSU is useless at powering 3.3V logic. You have to do power staging on board to guarantee that PCI and i2c stuff turns on after the bridge/soc. Some PSUs don't follow reset timings, or don't do them at all on standby rail. So if you do ATX power by the book, you may end up with improperly inited board, and 3.3V ICs booting up before the CPU. So, yes, most of ATX power supply functionality is already duplicated by most mobos
  - mmastrac 7y ago
    > ATX 5V is really unsuitable for USB power, and can play tricks on you. Would you mind elaborating on this?
    - baybal2 7y ago
      Poor transient response. Ringing on some PSUs. Out of spec ripple on most PSUs.
  - garaetjjte 7y ago
    >ATX 5V is really unsuitable for USB power, and can play tricks on you. Why? I don't think current motherboard duplicate 5V converter. >you may end up with improperly inited board, and 3.3V ICs booting up before the CPU. Why it cannot just hold reset line for these chips high until CPU started?
    - Gibbon1 7y ago
      A lot of peripheral IC's don't have reset lines. Sometimes this is a big big problem. You can end up with failure to come up maybe 1 in 10,000. Exactly the sort of thing that shows up late in development or worse in the field. Tip: If anyone tells you power supply and reset sequencing is 'easy' ignore them.
    - dezgeg 7y ago
      Holding chips in reset is not the only thing that matters. Complex chips may have power-sequencing restrictions; for example 1.8V power rail might need to be up before 3.3V, otherwise the chip gets damaged.
  - chungus_khan 7y ago
    Yeah, unfortunately we've thoroughly decayed past the good old AT days of being able to power logic straight off of the 5V. It helped that in those days there was one IBM making the PCs.

londons_explore 7y ago

Why does this still have 10 pins? 2 pins would be plenty. 12v Power, Ground, and an overlaid capacitively coupled 2 way data comms running at a few hundred khz to send and receive status messages, fan speeds, model/serial numbers, firmware/ temperatures, on/off commands, etc.

generatorguy 7y ago
to deliver 1500 watts at 12v through one pin would be 125 amps. 5 pins each with 25A I would think you’d want at least 14 gauge per pin and even then I think they would be rather warm.
- sjwright 7y ago
  If you’re sending 1500 watts directly into a motherboard, something is probably wrong. Massive power draws (CPU, GPU) would always get their own direct connection, just as they do today. Apply this simple rule of thumb: watts become heat. The only major exception to this is where the power has exited the computer via USB or similar.
  - jmgao 7y ago
    PCIe specifies that you can get 75W from the connector, which adds up quickly.
  - generatorguy 7y ago
    I haven't assembled a PC since the pentium 200 days. I recall hard drives, floppy drives, and the motherboard had their own power connections but not the CPU or GPU of the time. Still a single pin is probably something like a #18 gauge and would only be good for 10A before it gets too warm for comfort.
    - x0 7y ago
      I always thought that was why the big ATX connector has multiple 12V wires, multiple GND wires, etc. To push heaps of current, but using a normal gauge of wire, rather than something huge.

Melkman 7y ago

I wonder how easy this would make server local UPS systems. A battery with a single buck/boost converter should be enough as a power supply. Just need to add a mains fed charge circuit.

mmastrac 7y ago
Probably would allow very cheap power supplies w/built-in UPSes. 12V±5% voltage is the allowed range.
- baybal2 7y ago
  ±5% would not be that easy with current spikes from CPU and GPU. It's 300W-400W load going to near zero and back within microseconds.
  - chmod775 7y ago
    It's not black magic to handle that with a capacitor or two.
    - baybal2 7y ago
      It is, first the cap needs to ve huve enough, second ESR will need to be very, very low unless you want to cool the cap as well
- michaelt 7y ago
  Most desktop users would probably prefer a UPS that also ensured their monitor stayed on.
  - loeg 7y ago
    I actually leave my monitor off UPS intentionally. While I'm away, I'd rather my workstation survive a brownout or short loss of power and if I'm actively working, it's easy enough to move the monitor's power cable to the UPS to save my work and shut down. My CPU draws ~45W at idle; my monitor draws a whopping 130W — having it on battery materially shortens the off-AC runtime.

mmastrac 7y ago

12V makes so much more sense to be sending around - the losses at lower voltages are rough. It would be nice to replace legacy molex connectors with a more modern standard, however.

kbumsik 7y ago
> It would be nice to replace legacy molex connectors with a more modern standard Any example of the modern one? I personally have no issues with the current one. I am not sure if those molex connectors should be called as legacy.
- wlesieutre 7y ago
  Bulkiness is my main complaint, they can be a real nuisance in small form factor cases.
  - usrusr 7y ago
    And some recent examples are a terrible fit, I remember them aligning much smoother. A clear sign that manufacturers consider them second class. And nobody will complain, because it just strengthens the pre-existing assumption that the new plugs are better.
  - willis936 7y ago
    Industrial design demands this. A replacement connector should be difficult to remove and use sufficiently thick cables. Because of the requirements there is little room for improvement and thus we have used the same connectors for 30 years.
    - wlesieutre 7y ago
      The molex 2.36mm pins can apparently carry 8.5A, which at 12V gives you about 100W. That’s useful for some power hungry components, but I wish there were a smaller alternate 4-pin power cable standard that I could use to route power around to things like fans and SATA SSDs. Something in between the giant molex connectors and a 3-pin fan connector.

superkuh 7y ago

This makes sense for specific use case computers, specialty ones, etc. So it'll be adopted. And because of economies of scale it'll push into actual desktop computers and their mobos. Having to dissipate all that heat on/in the mobo will be terrible for actual desktop computers. But it'll happen anyway because it's better for corporations and the desktop market doesn't drive their decisions.

deleted 7y ago
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baybal2 7y ago
You already dissipate quite a lot in CPU VRMs. For everything 3.3V on mobo, a linear reg on board will still be more efficient than one in the PSU.
- superkuh 7y ago
  And the VRMs and associated circuitry are the most likely thing to die on the motherboard. The PSU, at least in my experience, is the most likely thing to die in a desktop computer. So now you have all the most likely to die components on the most expensive part of your desktop system. Being able to replace the PSU without the cost of the mobo is great for human people. For corporate people and their economies of scale it makes less sense than just making everything 1 thing and throwing it out when it breaks.
jleahy 7y ago
A typical CPU (or SSD even) uses a voltage of 0.9V currently, surely it doesn't matter whether the motherboard is converting 12V to 0.9V or 5V to 0.9V. Back when this stuff was originally designed 12V, 5V and 3.3V was all you needed (actually with the AT standard it was just 12V for motors and 5V for logic, that was pre-CMOS). Now every component requires a different voltage (if there's any standard it might be 1.8V or 1.2V), and to get several hundreds watts of power at 0.9V would require cables about an inch thick. 12V is the defacto standard for powering pretty much anything these days. Converting 12V into whatever you want is utterly trivial and incredibly efficient.

DiabloD3 7y ago

Four important things to consider: First, this already happened to some extent. Outside of drives and fans, the virtually all of the power used in your system is exclusively 12v; either from the 12v pins on your ATX24 or P4 or EPS12 connectors, or via the PCI-E connectors; very little non-drive or non-fan power is supplied via 3.3 or 5v rails. Second, almost all PSUs today use 12v DC to 3.3/5v DC converters to increase efficiency given how little 3.3v and 5v is required. The PSU itself is often designed internally as a high efficiency multi-module single rail 12v-only design. Third, Intel is not in a position to dictate anything. Intel has tried to float many changes in the standards (such as the WTX board standard (with matching incompatible mobo plug), and the BTX board standard (using ATX plugs)), and all failed. The only thing that stuck was using 4 and 8 pin PC Minifit Jr plugs (the same ones ATX, PCI-E and countless other plugs come from); and, annoyingly, somehow not compatible with PCI-E's pinout. Fourth, Intel is also not the dominant player in the field now, AMD is. They failed to get major changes through as the dominant player, what makes them think anyone cares to hear what they have to say today? It is unlikely AMD will ever ship machines that don't ship with normal ATX unless they just jettison the ATX24 altogether. Side note: 12v capacity: ATX24 144w, P4 192w, EPS12 336w, PCI-E 6 75w, PCI-E 8 150w, and the PCI-E slot itself 75w. A modern desktop could theoretically be ran off a dual EPS12 and a PCI-E 8+8 for the GPU; modern mobo designs run the CPU and RAM VRMs off the EPS12 entirely, modern GPU designs run the GPU VRMs off of PCI-E plugs and the VRAM VRMs off the PCI-E slot power, very little power of any voltage is supplied to the system via ATX24. Another side note: Any board that has a legitimately clean 5v rail for USB is not feeding it off the PSU directly. Any board that has absolutely garbage USB power probably committed this sin.

tedunangst 7y ago
Not sure I would classify AMD as the dominant player in the field just yet.
sp332 7y ago
Yeah, this is just rearranging some things to avoid California's new efficiency regulations. If you move the inefficent stuff to the motherboard, the PSU magically gets more efficient!

tus88 7y ago

Fuck them. Building retro PCs using modern power supplies will get ever more harder now.

sounds 7y ago
It'll be easy to find converters once the market shifts. There are enough retro builders that one will get built.

Animats 7y ago

Makes sense. Should have happened long ago. All those old voltages date from when +5 from the power supply was used directly by the logic. Facebook's Open Compute rack delivers only +12 to the boards and drives, and that's from 2011. There's a power supply in the base of the rack that takes in three-phase AC or 48 VDC or whatever and puts out +12VDC. All other conversion is on the board. This is just catching up desktops to where the data center went years ago.

jabl 7y ago
I recall Google mentioned something similar in some old explanation about their server designs.
- m463 7y ago
  I remember reading about that too -- they even put batteries on the motherboard to serve as distributed UPS systems.
laurencerowe 7y ago
I believe the Open Compute designs moved to 48 VDC for efficiency.
- Animats 7y ago
  Ah, they did.[1] The power busbars are in the same place, so you can't have both 12V and 48V in the same rack. The connectors are intentionally incompatible so you can't plug into the wrong voltage. [1] http://files.opencompute.org/oc/public.php?service=files&t=827d028fc82b4b55315a4d7815b43c78 http://files.opencompute.org/oc/public.php?service=files&t=8...

microcolonel 7y ago

So I guess this makes it cheaper to make lower-idling power supplies; or does a high quality current ATX PSU, like one of the Seasonic Titanium models, not meet the CEC standards for idle power?

yellowapple 7y ago

> PSU vendors don’t want to release ATX12VO products for DIY builders until there are motherboards that support ATX12VO. Motherboard vendors don’t want to create products until power supply makers support them. Seems like that could be addressed with one of two adapters: - A passive adapter cable with a female ATX connector (with the 3.3V and 5V pins disconnected) and male ATX12VO connector - An active adapter cable/board with a female ATX12VO connector, the necessary circuits to step voltages down to 3.3V and 5V, and a male ATX connector. One or both of these could happen today and immediately solve that chicken-and-egg problem for the custom market, no?

Jaruzel 7y ago
> An active adapter cable/board with a female ATX12VO connector, the necessary circuits to step voltages down to 3.3V and 5V, and a male ATX connector. I think this will definitely happen, as supplies of classic ATX PSUs start to dry up, and people need to keep powering their old machines. This situation already exists for old AT style vintage machines, being powered by ATX PSUs.
o_x 7y ago
This is already somewhat happening, but it's very niche: https://j-hackcompany.com/?product=j-hack-m2427-for-corsair-sf-series https://j-hackcompany.com/?product=j-hack-m2427-for-corsair-... https://smallformfactor.net/forum/threads/m2427-cable-management-freedom.10349/ https://smallformfactor.net/forum/threads/m2427-cable-manage...

vifya 7y ago

It was bound to happen eventually, there has been a long trend towards point-of-use regulation displacing multiple output supplies. I'm just surprised they went with 12V, and not 19V which has lower rectification losses, less power loss to wire/trace resistance, and a large existing design ecosystem from laptops where 19V has been the norm for years.

jacob019 7y ago
Or 24V or 36V, but alas 12V is the existing standard for legacy reasons so it's the path of least resistance for an overhaul of the PSU spec.
- deleted 7y ago
  [deleted]
- dev_tty01 7y ago
  "path of least resistance" -- Ha, I see what you did there.
thehobgoblin 7y ago
To me it seems like the ATX12VO specification is more of an endorsement of the direction PC power supplies seem to be moving in rather than a from-scratch redesign. It would be nice to have higher voltage (19V, 24V or perhaps higher) for a single voltage supply, but it would be a far bigger change to the overall PC ecosystem.
- deleted 7y ago
  [deleted]
numpad0 7y ago
Why is it 19V for laptops? I had suspected it’s to compensate for voltage drop at linear regulators. Batteries are either 11.1(3.7v 4 cells) or 14.8(3.7v 3 cells 1-3 parallel) and these voltages doesn’t seem immediately consistent with ATX12V to me.

PaulDavisThe1st 7y ago

I love computers with 12VDC native power jacks. Why? My solar-powered van (interior only, the engine is still diesel) is 12VDC everywhere, and that's good clean battery DC, not some noisy-ass AC/DC conversion. I love it so much that 2 of the last 3 computers I built (on an ATX form factor) were 12VDC native. I have external AC/DC power supplies for them, but when travelling/living in a solar-powered environment, I get to just plug them straight into the clean juice. Sadly, monitors used to be this way too - they came with external power bricks and were 12VDC native. But sometime in the mid-2000's, something changed. My guess is that someone figured out how to shrink the necessary converters to a size that made it more "sensible" to put them inside the monitor. Result: almost impossible now to find a monitor you connect to a 12VDC supply. The one I have in the van took me months to find on ebay back in 2015. The only exception are "TV" monitors specifically made for RVs, which is great and all, except that most of them are crap compared to a modern monitor. One small problem with plugging 12VDC native computers into a solar system: it's not atypical for the solar charge controller to drive the charge voltage over 14V, at which point most internal "PSUs" designed for 12V will shutdown. You need a voltage regulator between you and the battery-terminal voltage.

whoopdedo 7y ago
My 4k Monoprice monitor is 12V. So it's not as impossible as you think.
jniedrauer 7y ago
Do you find that it's more power efficient to run a custom built machine like that? I would think that using a laptop as your daily driver would stretch your battery bank further, since it's designed from the ground up for battery power. I lived off solar power for a while, and that was my thinking. I never did the math to verify it though.
- PaulDavisThe1st 7y ago
  I haven't done any measurements. What I will say is that the machine I used to use in the van lost its video output (the perils of onboard graphics), and I've found it impossible to source a reasonable replacement mobo. As a result, I've switched back to using a laptop (lenovo Y700) in the van. What I notice as a potential improvement is that it effectively lets me store an extra X hours of power for computing, because I'm adding the laptop battery to the overall storage. Compared to my "house batteries", the laptop batteries are of course very small. But getting (say) 3 hours of work time stored up in the laptop does seem like a plus, especially on cloudier days.

ksec 7y ago

I actually want a spec that is similar to Apple's Mac Pro, there should be Zero Cables.

ChuckMcM 7y ago

I remember the days when Microsoft and Intel would host the "PCxx" spec (where xx was the last two digits of the year) and tell everyone what all the standards for desktop machines were going to be for the next few years. Those days are gone though. 12V rail PSUs are nice for a number of reasons but I always liked that you could feed your DC input from the AC side or a battery and have a "free" UPS at the same time. It is a bit tricky with a switching supply since you don't want to have the battery seeing 25Khz power outages as the switcher turns on and off but its very doable. With a little bit of instrumentation you could have the PC itself control charging and monitoring the battery itself so only a minimal amount of hardware needed to give every motherboard its own UPS.

effie 7y ago
I am very much interested in this, using DC power sources is the future. How do I go around adding a 12V DC power supply to the ordinary ATX computer? Can you find some links for this?
- ChuckMcM 7y ago
  Such supplies exist for some levels of power. Very popular in the MiniITX community where power levels are < 300W.[1]. There is also a wealth of material on developing DC to DC converters and a number of modules for the same. For a non-engineer putting something together I would look at DC-DC converter modules (see https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=dc%20to%20dc%20converter https://www.digikey.com/products/en/power-supplies-board-mou...) that provided the necessary power rails, at the power level that was required. Such a solution would not be compact and integrated like one that was designed from scratch to be used in this way, but would certainly work. I used one of the MiniITX supplies to power a system that is mounted in a box on a tree with a solar panel charging a deep cycle battery. It is the download/storage point for a number of wildlife cameras nearby. [1] https://www.amazon.com/250w-DC-ATX-Power-Supply-Supplies/dp/B00NB6U3TS https://www.amazon.com/250w-DC-ATX-Power-Supply-Supplies/dp/...
  - effie 7y ago

gggmaster 7y ago

This will make motherboards more expensive and fragile. Desktop chipsets from Intel can only support two generations of processors. While a good PSU can have ten years of warranty.

guerrilla 7y ago
A plan for planned obsolescence?
- gggmaster 7y ago
  Delivering only 12V has its own pros, so I will give them the benefit of doubt. But I think this move will increase my cost of building desktops.

russdill 7y ago

In one sense this feels like pushing the efficiency problem under the rug. There's a requirement for power supplies to meet a certain efficiency standard, and generating 3.3v and 5v rails are pushing that number down. Solution? Move that task to the motherboard where they won't count against the power supply efficiency requirement. Of course, from a purely engineering perspective, it really does make sense and it's overdue.

simias 7y ago
The motherboard "knows more" than the PSU though, it should be able to better deal with these idle power situations by shutting down things that aren't used anymore and powering them back up when needed. An external PSU would have tighter constraints regarding power availability and wouldn't be able to optimize the power profile quite as aggressively since they don't really know exactly what they're driving.
- russdill 7y ago
  Many DC-DC supplies have auto-standby/idle modes that take care of this problem in an automatic way.
Faaak 7y ago
Exactly. I'm pretty sure that once the DC-DC converters are mainly placed in the motherboard, they won't be audited for efficiency anymore and global efficiency will plummet. A shame
- undersuit 7y ago
  Decreasing efficiency of the motherboard would mean it needs more power, meaning they would require larger power supplies in addition to being a new specification.
  - detaro 7y ago
    Decreasing efficiency of their platform is also not really something Intel has an interest in, since it makes them look bad.

jaclaz 7y ago

Only as anecdata, in my practical experience over the years, I needed to change many power supplies[1], and very few motherboards. (excluding replacements due to upgrades) I would go a little bit further and say that the PSU is probably the most replaced "standard" part of a PC, followed by hard disks. I also a couple times repaired a PSU replacing this or that failed component, but it is simply not worth the time and money, as spare new PSU's are cheap enough, the replacing is very easy whilst even procuring a single chip or capacitor is complex for non-professionals, besides the soldering tools, etc. Hopefully the parts that age or however tend to fail will remain in the (easily replaceable) PSU, otherwise we will see an increase in replaced motherboards. Some sort of (standard) "daughterboard" with the voltage regulating components would have made more sense (to me), but surely it makes less sense from an industrial manudacturing point of view. [1] be it due to capacitors, power transistors or mosfets or whatever, and due to whatever reasons, be it aging, power surges, etc.

unlinked_dll 7y ago
Are you buying bottom of the barrel PSUs? I've had the same Corsair unit in three machines over the last decade. Works perfectly fine.
- aliswe 7y ago
  Might be the power grid.
- jaclaz 7y ago
  >Are you buying bottom of the barrel PSUs? If you mean that "standard" OEM PSU's (think Asus, Fujitsu, IBM/Lenovo and a few - mini-ITX Shuttle cases) are "bottom of the barrel", yes. Then, since often an used, original, non-standard (say) IBM/Lenovo PSU can be found for a mere 100-150 € on e-bay, I started getting el-cheapo (though not el-cheapest) ones with no appreciable decrease (or increase) in durability, putting them externally and re-mapping the cables. For the mini-ITX cases (that use a not-very-common form factor) I gutted new 1U server PSU's and managed to fit them in. The PC I am writing this with (ASUS) is 2008 and I replaced a PSU in 2012 and one in 2016 or 2017, cannot remember. Out of the four IBM/Lenovo's I have at another office, dated 2010 or 2011, two have still their original PSU, two have the external adapted ATX, no other parts replaced. All in all (and for whatever reasons) I would estimate that over a 5-10 years lifetime of a system[1] there are: 1-2 replacement of PSU's 1 replacement of hard disk(s) No replacement of other parts, let alone the motherboard. Sice 2012 I am at the third Fujitsu ThinClient (used as router) with PSU failing (in this case they are so cheap second hand that I change the whole little machine). [1] the mini-ITX's (there were three of them) before being decommissioned) lasted 2003-2018, i.e. 15 years, running NT 4.0 or 2K 24/7 each with 2 PSU replacements, the last one, being a server grade PSU most probably would be just fine for another five or more years.

rb808 7y ago

Why 12v though? What requires that much voltage? The chips are running at a few volts. Spinning drives are gone, is it just for fans? Seems silly to provide 12v then shift it down again.

belval 7y ago
While I don't know the exact component that needs 12V, you have to keep in mind that your typical computer draws about 300W under a small load. 300W/12V means 25 amps. Reduce the voltage without lowering the power consumption and you need bigger wires to handle the increase in amps.
mcv 7y ago
True, but motherboards need to shift down anyway. The motherboard controls the voltage of the CPU, and that can be anything.

jotm 7y ago

Not the first time Intel is pushing for tighter VRM integration. Haswell had FIVR, which I think was pretty revolutionary, the die itself contained VRMs for the CPU, IGP, memory and more. Sadly, they gave up on it, probably because it made the processors run hot as hell. There's not enough die area to cool all of that plus the processing cores and multiple controllers themselves

AncientTree 7y ago

The big advantage could be finally moving the PSU out of the case, and having it as just an external power brick. This will make systems significantly lighter and smaller (and thus more portable), take heat out of the case, and improve airflow. You can already buy 330w laptop chargers - just beef them up and you could easily run a mid-grade gaming PC. https://www.amazon.com/Dell-Adapter-DA330PM111-ADP-330AB-332-1432/dp/B00CGA5JQM/ref=sr_1_6?keywords=330w+laptop+charger&qid=1583854491&sr=8-6 https://www.amazon.com/Dell-Adapter-DA330PM111-ADP-330AB-332... You can already buy