5 ms·

> Components like RAMs, USB, and M.2 SSDs don't use 12v <snip> but 3.3V or 5V. The motherboard will be responsible for managing voltages for these components.

by elric 3y ago

> Components like RAMs, USB, and M.2 SSDs don't use 12v <snip> but 3.3V or 5V. The motherboard will be responsible for managing voltages for these components. Surely this will simply move part of the complexity from the PSU to the motherboard? Resulting in more efficient and simple PSUs, but more inefficient and complex motherboards? I've only ever had motherboards fail because of leaky capacitors or busted voltage regulators. The only PSU failure I've ever had was on account of a broken fan. Won't this lead to more motherboard failures? The cynic in me thinks that Intel would be fine with that, because that way they can sell more motherboard components.

photonbeam 3y ago
Half the mainboard is already just a PSU, this just means the big initial step down from 240v/120v is in a separate shielded/grounded box I somewhat wished they’d gone to 48vdc instead of 12vdc, though to further reduce cabling, but I guess that would be a big change, the 12vo seems much simpler
- eksu 3y ago
  this is a computer not a car, 48v seems overkill and dangerous. components use 12v, 5v, or 3.3v in pcs currently. why do the step down from 48->12 instead of running 12v naturally? 12v is also what is used by the most power hungry components of a PC (GPU).
  - dist-epoch 3y ago
    The most power hungry component, the CPU, uses 1-1.5v. The GPU voltage is also step down to 1-1.5v by graphics cards VRMs.
    - connicpu 3y ago
      Power regulators that can efficiently produce the 1-1.5v output with the most minimal noise generally have lower maximums on their input voltage as well. In designing some of my own IoT devices I've looked into a fair number of power regulator ICs and 36V is a common maximum input voltage. The efficiency curves on the datasheets also usually show the efficiency gets lower the higher the input DC voltage. In a power regulator, inefficiency means even more heat you have to dissipate, not great in a GPU. I'm sure the GPU would love to take even lower voltage if it could, but 12V is the compromise we've decided on to get decent efficiency without requiring insanely thick conductors.
  - deleted 3y ago
    [deleted]
  - photonbeam 3y ago
    usbc can do 48v, its not that dangerous
  - jauntywundrkind 3y ago
    48v seems vastly safer. There's 1/4 the thermal heating for equivalent power. The new high density 12VHPWR connector for GPUs has been melting down & had to get basically redesigned. That would not have been a problem at all on 48V. There shouldn't be an intermediary step down to 12V. Google's been doing direct step down from 48V->~1V with GaN fets for half a decade, which is vastly more power efficient than the two step 277V->12->1V that many server systems go through. It'd also be amazing to have usb-c extended power (48v) be something we could just add for free, essentially. (Alas this is complicated by needing to step down to lower voltages too, necessities some semiconductors in the delivery path to usb-c, which would have some voltage drop. This strongly implies to me something more like 52V or 54V would be ideal instead of 48V.) For anything that typically runs under 100W, I agree that 48V is ridiculous. But I would love love love to see some motherboards for ThreadRipper that have GaN fet for direct conversion from 48V, or stuff like that. It'd be pretty niche. But it should be an option! One of the big potential winners could be people with solar; being able to run your system directly off your solar bank would save double digits percent of power, versus inverting then converting back. You're right that in the immediate term we'd see a lot of intermediary conversions. I'd love to have a better game plan, for not just motherboards but other components to expect either 48v or wider voltage inputs. Non-trivial to support 10-60V but if that was a market expectation & not a niche need we'd see very affordable solutions spring up practically overnight. There's already a range of usb-c focused power converters that are exceedingly cheap that could step in for this need! Edit: seems like Google is using two stage conversion primarily, but not necessarily 4:1 48V:12V. Their fixed ratio converter seems to have a 6:1 mode (8V) target as well, or be configurable for even bigger ratio (they said up to 12:1 in their talk). As of 2019, a bit of change of tune from original 2016 ambitions. Good talk? https://youtu.be/aBkz2JR4UVs https://youtu.be/aBkz2JR4UVs
  - cactacea 3y ago
    48V DC is completely safe and not dangerous whatsoever
    - hulitu 3y ago
      As a computer, i find your trust in technology, amusing. /s It depends on the current. Your 48 V suppply won't supply microamps, but Amps.
  - epcoa 3y ago
    > 48v seems overkill and dangerous. In fact the exact opposite is true, it is safer in practice. In a true fault condition into flesh the currents involved aren’t substantially less safe (4x microamps is still microamps). With protection circuitry and current limiting, the permitted currents are that much lower, which is easier to deal with.
    - hulitu 3y ago
      > With protection circuitry and current limiting which are cut because of costs.
- crote 3y ago
  48V is simply too much for most electronics. Finding parts to handle 12V or even 20V is pretty trivial, but at 48V you're going to have serious trouble sourcing it at a reasonable price. Maybe this will change as 240W USB-C becomes common, though. An additional issue is that the sweet spot for voltage conversion is around the 1:10 ratio. Going 120V -> 12V -> 1.2V makes a lot of sense, 120V -> 48V -> 1.2V less so.
  - bsder 3y ago
    > Finding parts to handle 12V or even 20V is pretty trivial, but at 48V you're going to have serious trouble sourcing it at a reasonable price. I don't buy this at all. 48V and 96V are standard telecom DC voltages. Those parts already exist. If anything, this would be a big boon as it would enable using both telecom and consumer parts interchangably (thus increasing volume on both).
    - pcdoodle 3y ago
      Even resistors have a rated voltage. 0402 for instance is about 25V.
      - bsder 3y ago
        Nah, you just have to size things correctly. Passives are fine. You use a 100K resistor if you really need to keep things at 0402 for 100V. (P=V^2/R = 0.1 watt) A 0.1uF 0402 ceramic cap rated at 100V is half a cent. The biggest problem are your power transistors with max Vgs. That requires a bit of care at 24V; requires quite a bit more care at 48V; requires very specialized topologies at 96V.
        pcdoodle 3y ago
        Thanks, learned something new.
- hulitu 3y ago
  > Half the mainboard is already just a PSU So the solution is to.make 75 % or even 100 % of the mainboard, the PSU. /s
  - photonbeam 3y ago
    Yes, seriously (for the 75%) Its like a code refactoring Mains power is dangerous and should be kept in a box separate from current limited lower voltage DC, which could be on the mainboard instead. Nothing actually needs 12v, it all just converts locally to the desired voltage which is why the mainboard is already a psu
Gravityloss 3y ago
The motherboard can do the conversion next to where the low voltage is needed, reducing the distance and thus the amount of copper needed.
- deleted 3y ago
  [deleted]
kyrra 3y ago
GN talked about this 8 months ago here: https://www.youtube.com/watch?v=Zc9oRKexV_s&t=4m15s https://www.youtube.com/watch?v=Zc9oRKexV_s&t=4m15s That timestamp is where they address this issue. It seems the argument is that in sleep mode (low power modes), the system will draw overall less power with ATX12VO vs today's standards. Further, if you go directly to the specs: https://edc.intel.com/content/www/us/en/design/products-and-solutions/processors-and-chipsets/alder-lake-s/atx12vo-12v-only-desktop-power-supply-design-guide/2.0/power-supplies-and-alternative-low-power-mode/ https://edc.intel.com/content/www/us/en/design/products-and-..., you can see they talk about ALPM (alternative low power mode) which seems to be the reasons for this design.
- hakfoo 3y ago
  All these more and more complex sleep modes on desktop seem like they're solving problems people don't have. I thought we solved suspend-to-RAM and suspend-to-disc years ago; wasn't the point of the +5VSB rail to keep stuff like RAM refresh going? Maybe on laptops where people are regularly suspending them, it's a bigger deal, but those are using bespoke power solutions and so ATX12VO solves nothing. If it's so desperately vital that they have some "it's low-power, but still doing something like checking for notifications" mode, couldn't this be done with a mini-coprocessor with the specs of a RasPi 1 running on +5VSB?
- hulitu 3y ago
  Windows will take care of it. It has to check for updates even in sleep. /s
toast0 3y ago
A lot of the complexity already moved to motherboards. CPU and ram voltages are generated on the motherboard by necessity --- they don't run at 5v or 3.3v, they are adjustable in small steps based on load and configuration.
gosub100 3y ago
funny if we end up going full-circle back to replaceable VRMs like they had on dual CPU boards 25 years ago.
Arnavion 3y ago
I'm not too worried about the complexity. What I *am* worried about is that your number of SATA power ports on your motherboard will become the limiting factor for how many SATA drives you can connect. The number of SATA *data* ports on the motherboard was not as much of a limiting factor because you can add data ports through M.2 / PCIe adapters. For example, the "MSI Pro H610M 12VO" hyperlinked in the article has a manual that shows it as having two SATA power ports, and an image shows one such port connecting to a single drive. Now I imagine this is a simplified illustration and maybe each port will have enough power to supply 3-to-4 HDDs (depending on current rating of the HDDs of course), but that's still a max of 8 HDDs. Meanwhile the non-12VO PSU I use has four ports available that can each connect to 3-to-4 HDDs each, so a max of 16 HDDs, and it definitely has enough spare power to support them because I sized the PSU for that need.
- marcosdumay 3y ago
  Why not get a SATA PSU just like you are adding a dara adapter?
  - Arnavion 3y ago
    So two PSUs / power bricks? I'll just stick with non-12VO PSUs and boards as long as I can, and if enough people think like me then mobo manufacturers will continue stalling on 12VO.
    - namibj 3y ago
      No, an active converter from a PCIe power connector or such to SATA power. Perhaps integrated in many sata cards.
    - marcosdumay 3y ago
      Does the power brick come exclusively with the motherboard connector? I'm pretty sure you will be able to get one with extra connectors for power-hungry peripherals. Your adapter board that will need an extra pair of switching power supplies. I doubt you'll even need an extra board. (Not that I expect anybody to actually adopt the standard. People will continue to drag their feet, mostly because there aren't enough gains to switch.)
shadowpho 3y ago
Motherboard already manages a lot of low voltage regulators. The density and design of motherboard is much more suited to this then PSU
bryanlarsen 3y ago
USB uses 5V, 9V, 15V, 20V, 28V, 36V or 48V. M.2 uses 3.3V. But those are all interface voltages, they're almost always stepped down on device to the actual voltage used. RAM doesn't have an interface voltage, it uses the voltage supplied, typically around 1.2V.
- Dylan16807 3y ago
  The vast majority of USB ports on a computer are using 5V. And M.2 using 3.3V is kind of weird and limiting. Though RAM does its own conversion now, starting with DDR5.
- duskwuff 3y ago
  > USB uses 5V, 9V, 15V, 20V, 28V, 36V or 48V. M.2 uses 3.3V. But those are all interface voltages USB uses 3.3v signalling up through USBHS. (USBSS is 1V differential.) The higher voltages are for power delivery only.
dist-epoch 3y ago
The problem with the current design is how to divide the power between the 12v, 5v and 3.3v rails. If you put most on 12v but you have a motherboard pulling more from 5v, you have a problem. Currently power supplies divide it based on average motherboard usage, but these slowly change, and your old power supply will stop having the optimum mix. The solution is to output it all on one rail.
- wtallis 3y ago
  For at least ~20 years, the typical solution for ATX power supplies has been to make one big 12V rail, and then tack on up to about 120W of converters to step down from 12V to 5V and 3.3V. In practice, this has meant that anyone running less than a dozen disk drives has excess capacity on their 5V rail, but no capacity from the 12V rail was sacrificed to provide that. There was a time when the 5V and 3.3V rails on ATX power supplies weren't vestigial, but that era was shorter than the current era of all the major high-power components using a 12V supply.
  - toast0 3y ago
    Somewhere in the last two decades, multiple 12v rails was popular, but I think we've gone back to single rails.
    - wtallis 3y ago
      For a while, some PSUs were dividing their single 12V rail into separate outputs with individual current limits, to more closely adhere to older ATX standards. Consumers were not interested in managing the complexity of balancing power between virtual rails while CPU and GPU power were skyrocketing.

by elric 3y ago

photonbeam 3y ago

Half the mainboard is already just a PSU, this just means the big initial step down from 240v/120v is in a separate shielded/grounded box I somewhat wished they’d gone to 48vdc instead of 12vdc, though to further reduce cabling, but I guess that would be a big change, the 12vo seems much simpler

eksu 3y ago
this is a computer not a car, 48v seems overkill and dangerous. components use 12v, 5v, or 3.3v in pcs currently. why do the step down from 48->12 instead of running 12v naturally? 12v is also what is used by the most power hungry components of a PC (GPU).
- dist-epoch 3y ago
  The most power hungry component, the CPU, uses 1-1.5v. The GPU voltage is also step down to 1-1.5v by graphics cards VRMs.
  - connicpu 3y ago
    Power regulators that can efficiently produce the 1-1.5v output with the most minimal noise generally have lower maximums on their input voltage as well. In designing some of my own IoT devices I've looked into a fair number of power regulator ICs and 36V is a common maximum input voltage. The efficiency curves on the datasheets also usually show the efficiency gets lower the higher the input DC voltage. In a power regulator, inefficiency means even more heat you have to dissipate, not great in a GPU. I'm sure the GPU would love to take even lower voltage if it could, but 12V is the compromise we've decided on to get decent efficiency without requiring insanely thick conductors.
- deleted 3y ago
  [deleted]
- photonbeam 3y ago
  usbc can do 48v, its not that dangerous
- jauntywundrkind 3y ago
  48v seems vastly safer. There's 1/4 the thermal heating for equivalent power. The new high density 12VHPWR connector for GPUs has been melting down & had to get basically redesigned. That would not have been a problem at all on 48V. There shouldn't be an intermediary step down to 12V. Google's been doing direct step down from 48V->~1V with GaN fets for half a decade, which is vastly more power efficient than the two step 277V->12->1V that many server systems go through. It'd also be amazing to have usb-c extended power (48v) be something we could just add for free, essentially. (Alas this is complicated by needing to step down to lower voltages too, necessities some semiconductors in the delivery path to usb-c, which would have some voltage drop. This strongly implies to me something more like 52V or 54V would be ideal instead of 48V.) For anything that typically runs under 100W, I agree that 48V is ridiculous. But I would love love love to see some motherboards for ThreadRipper that have GaN fet for direct conversion from 48V, or stuff like that. It'd be pretty niche. But it should be an option! One of the big potential winners could be people with solar; being able to run your system directly off your solar bank would save double digits percent of power, versus inverting then converting back. You're right that in the immediate term we'd see a lot of intermediary conversions. I'd love to have a better game plan, for not just motherboards but other components to expect either 48v or wider voltage inputs. Non-trivial to support 10-60V but if that was a market expectation & not a niche need we'd see very affordable solutions spring up practically overnight. There's already a range of usb-c focused power converters that are exceedingly cheap that could step in for this need! Edit: seems like Google is using two stage conversion primarily, but not necessarily 4:1 48V:12V. Their fixed ratio converter seems to have a 6:1 mode (8V) target as well, or be configurable for even bigger ratio (they said up to 12:1 in their talk). As of 2019, a bit of change of tune from original 2016 ambitions. Good talk? https://youtu.be/aBkz2JR4UVs https://youtu.be/aBkz2JR4UVs
- cactacea 3y ago
  48V DC is completely safe and not dangerous whatsoever
  - hulitu 3y ago
    As a computer, i find your trust in technology, amusing. /s It depends on the current. Your 48 V suppply won't supply microamps, but Amps.
- epcoa 3y ago
  > 48v seems overkill and dangerous. In fact the exact opposite is true, it is safer in practice. In a true fault condition into flesh the currents involved aren’t substantially less safe (4x microamps is still microamps). With protection circuitry and current limiting, the permitted currents are that much lower, which is easier to deal with.
  - hulitu 3y ago
    > With protection circuitry and current limiting which are cut because of costs.
crote 3y ago
48V is simply too much for most electronics. Finding parts to handle 12V or even 20V is pretty trivial, but at 48V you're going to have serious trouble sourcing it at a reasonable price. Maybe this will change as 240W USB-C becomes common, though. An additional issue is that the sweet spot for voltage conversion is around the 1:10 ratio. Going 120V -> 12V -> 1.2V makes a lot of sense, 120V -> 48V -> 1.2V less so.
- bsder 3y ago
  > Finding parts to handle 12V or even 20V is pretty trivial, but at 48V you're going to have serious trouble sourcing it at a reasonable price. I don't buy this at all. 48V and 96V are standard telecom DC voltages. Those parts already exist. If anything, this would be a big boon as it would enable using both telecom and consumer parts interchangably (thus increasing volume on both).
  - pcdoodle 3y ago
    Even resistors have a rated voltage. 0402 for instance is about 25V.
    - bsder 3y ago
      Nah, you just have to size things correctly. Passives are fine. You use a 100K resistor if you really need to keep things at 0402 for 100V. (P=V^2/R = 0.1 watt) A 0.1uF 0402 ceramic cap rated at 100V is half a cent. The biggest problem are your power transistors with max Vgs. That requires a bit of care at 24V; requires quite a bit more care at 48V; requires very specialized topologies at 96V.
      - pcdoodle 3y ago
        Thanks, learned something new.
hulitu 3y ago
> Half the mainboard is already just a PSU So the solution is to.make 75 % or even 100 % of the mainboard, the PSU. /s
- photonbeam 3y ago
  Yes, seriously (for the 75%) Its like a code refactoring Mains power is dangerous and should be kept in a box separate from current limited lower voltage DC, which could be on the mainboard instead. Nothing actually needs 12v, it all just converts locally to the desired voltage which is why the mainboard is already a psu

Gravityloss 3y ago

The motherboard can do the conversion next to where the low voltage is needed, reducing the distance and thus the amount of copper needed.

deleted 3y ago
[deleted]

kyrra 3y ago

GN talked about this 8 months ago here: https://www.youtube.com/watch?v=Zc9oRKexV_s&t=4m15s https://www.youtube.com/watch?v=Zc9oRKexV_s&t=4m15s That timestamp is where they address this issue. It seems the argument is that in sleep mode (low power modes), the system will draw overall less power with ATX12VO vs today's standards. Further, if you go directly to the specs: https://edc.intel.com/content/www/us/en/design/products-and-solutions/processors-and-chipsets/alder-lake-s/atx12vo-12v-only-desktop-power-supply-design-guide/2.0/power-supplies-and-alternative-low-power-mode/ https://edc.intel.com/content/www/us/en/design/products-and-..., you can see they talk about ALPM (alternative low power mode) which seems to be the reasons for this design.

hakfoo 3y ago
All these more and more complex sleep modes on desktop seem like they're solving problems people don't have. I thought we solved suspend-to-RAM and suspend-to-disc years ago; wasn't the point of the +5VSB rail to keep stuff like RAM refresh going? Maybe on laptops where people are regularly suspending them, it's a bigger deal, but those are using bespoke power solutions and so ATX12VO solves nothing. If it's so desperately vital that they have some "it's low-power, but still doing something like checking for notifications" mode, couldn't this be done with a mini-coprocessor with the specs of a RasPi 1 running on +5VSB?
hulitu 3y ago
Windows will take care of it. It has to check for updates even in sleep. /s

toast0 3y ago

A lot of the complexity already moved to motherboards. CPU and ram voltages are generated on the motherboard by necessity --- they don't run at 5v or 3.3v, they are adjustable in small steps based on load and configuration.

gosub100 3y ago

funny if we end up going full-circle back to replaceable VRMs like they had on dual CPU boards 25 years ago.

Arnavion 3y ago

I'm not too worried about the complexity. What I *am* worried about is that your number of SATA power ports on your motherboard will become the limiting factor for how many SATA drives you can connect. The number of SATA *data* ports on the motherboard was not as much of a limiting factor because you can add data ports through M.2 / PCIe adapters. For example, the "MSI Pro H610M 12VO" hyperlinked in the article has a manual that shows it as having two SATA power ports, and an image shows one such port connecting to a single drive. Now I imagine this is a simplified illustration and maybe each port will have enough power to supply 3-to-4 HDDs (depending on current rating of the HDDs of course), but that's still a max of 8 HDDs. Meanwhile the non-12VO PSU I use has four ports available that can each connect to 3-to-4 HDDs each, so a max of 16 HDDs, and it definitely has enough spare power to support them because I sized the PSU for that need.

marcosdumay 3y ago
Why not get a SATA PSU just like you are adding a dara adapter?
- Arnavion 3y ago
  So two PSUs / power bricks? I'll just stick with non-12VO PSUs and boards as long as I can, and if enough people think like me then mobo manufacturers will continue stalling on 12VO.
  - namibj 3y ago
    No, an active converter from a PCIe power connector or such to SATA power. Perhaps integrated in many sata cards.
  - marcosdumay 3y ago
    Does the power brick come exclusively with the motherboard connector? I'm pretty sure you will be able to get one with extra connectors for power-hungry peripherals. Your adapter board that will need an extra pair of switching power supplies. I doubt you'll even need an extra board. (Not that I expect anybody to actually adopt the standard. People will continue to drag their feet, mostly because there aren't enough gains to switch.)

shadowpho 3y ago

Motherboard already manages a lot of low voltage regulators. The density and design of motherboard is much more suited to this then PSU

bryanlarsen 3y ago

USB uses 5V, 9V, 15V, 20V, 28V, 36V or 48V. M.2 uses 3.3V. But those are all interface voltages, they're almost always stepped down on device to the actual voltage used. RAM doesn't have an interface voltage, it uses the voltage supplied, typically around 1.2V.

Dylan16807 3y ago
The vast majority of USB ports on a computer are using 5V. And M.2 using 3.3V is kind of weird and limiting. Though RAM does its own conversion now, starting with DDR5.
duskwuff 3y ago
> USB uses 5V, 9V, 15V, 20V, 28V, 36V or 48V. M.2 uses 3.3V. But those are all interface voltages USB uses 3.3v signalling up through USBHS. (USBSS is 1V differential.) The higher voltages are for power delivery only.

dist-epoch 3y ago

The problem with the current design is how to divide the power between the 12v, 5v and 3.3v rails. If you put most on 12v but you have a motherboard pulling more from 5v, you have a problem. Currently power supplies divide it based on average motherboard usage, but these slowly change, and your old power supply will stop having the optimum mix. The solution is to output it all on one rail.

wtallis 3y ago
For at least ~20 years, the typical solution for ATX power supplies has been to make one big 12V rail, and then tack on up to about 120W of converters to step down from 12V to 5V and 3.3V. In practice, this has meant that anyone running less than a dozen disk drives has excess capacity on their 5V rail, but no capacity from the 12V rail was sacrificed to provide that. There was a time when the 5V and 3.3V rails on ATX power supplies weren't vestigial, but that era was shorter than the current era of all the major high-power components using a 12V supply.
- toast0 3y ago
  Somewhere in the last two decades, multiple 12v rails was popular, but I think we've gone back to single rails.
  - wtallis 3y ago
    For a while, some PSUs were dividing their single 12V rail into separate outputs with individual current limits, to more closely adhere to older ATX standards. Consumers were not interested in managing the complexity of balancing power between virtual rails while CPU and GPU power were skyrocketing.