4 ms·

$145 is pretty steep, and I'd like to see the Vpp (also called ripple) before considering this. I currently use picoPSU (ASIN B005TWE5E6), 50W and 80W versions

$145 is pretty steep, and I'd like to see the Vpp (also called ripple) before considering this. I currently use picoPSU (ASIN B005TWE5E6), 50W and 80W versions to power 7th and 8th gen atoms and celerons. I use a "UPS" style 12VDC PSU connected to a fairly large sealed lead acid battery - about 4x the volume of a standard UPS battery. As far as my measurements go with the induced noise from the PSU for radio reception work, it seems to work pretty good. I've looked at using SBCs instead, but you're never really going to get away from buck/boost on boards, since some things need 3.3 or less volts (memory, etc). The picoPSU also have survived for years up in elevator attics with all of the machinery and dust. never had an outage caused by the picoPSU or the attached 12V UPS stuff. I wonder if it is possible to run more than one board off the same PSU. I know you can run a board off multiple PSUs, but is the inverse true? If i ever get a new batch of these 25W TDP computers racked, having 2 of these connected to two UPS and 6 computers might be cool. It's just the ATX connector that needs population, i use NVME whenever possible, no GPU, no cards, just USB and ethernet onboard.

rektide 4y ago
> I wonder if it is possible to run more than one board off the same PSU. Absolutely. There's something I can't remember about signal lines that need to be set up, but yet, people have been running multiple computers off as single supply for a long long long time now. Also worth warning people ahead of time, it's hard to predict what kind of specific power consumption a motherboard will have. There's so many power rails going in. 3.3V, 5V, 12V, -3.3V... Making sure that each rail is adequately rated for additional motherboards can be a challenge. Ideally one would test each supply line, one by one, to try & figure things out, & compare against rated specs of the power supply. Intel's been pushing a new spec called ATX12VO, short for 12-volts-only, which does away with all the other rails & has the motherboard expect 12v. This would make it much easier to understand what power consumption is. I do seem to recall some of the new ATX specs (3.0?) also kind of expect power-consumers to declare how much power they expect to use, as a safety/planning feature, which could complicate this one easy-to-do hack (unless there's some way for the additional motherboard/motherboards to also declare their power draw). This might only be ATX3.0's new 12VHPWR connector, which works alongside PCIe 5.0-- not sure if it also impacts motherboards or not.
- robocat 4y ago
  > Making sure that each rail is adequately rated for additional motherboards can be a challenge Buy a cheap inline tester and leave it always in? Something like: https://www.google.co.nz/search?q=Power+Supply+Tester+Digital+LCD+20%2F24+Pin+PSU+ATX+BA4 https://www.google.co.nz/search?q=Power+Supply+Tester+Digita...
- paulmd 4y ago
  These days the 3.3v rail and -3.3v rail are practically vestigial (iirc the major consumer on those rails was floppy disk drives...) and 5V is mostly used to drive SSDs and USB devices. Almost everything runs off 12V these days - which is the whole point behind the 12VO standard, just make everything use 12V and step it down at the point-of-consumption for the handful of things that still need something else. So basically I wouldn't worry about motherboard compatibility due to 5v, 3.3v, and -3.3v rails - there just isn't much of anything still being done on those rails, and the things that do use it pretty much are the same across motherboards (because they're things that are plugged into the motherboard, not the motherboard itself).
  - mschuster91 4y ago
    > and 5V is mostly used to drive SSDs and USB devices. The most important 5V rail is 5VSB - it powers wake-on-LAN and on some systems wake-via-bluetooth. The interesting question is, is it more efficient to always let 12V->5V regulators run for 5VSB or to use an extremely small separate regulator?
    - glowingly 4y ago
      To be fair, something is stepping it down from AC, and many modern PSUs step everything down from a common DC rail using DC-DC conversion (i.e, 12V, 5V, 3.3V, etc are all generated from a source DC voltage). Then things like the CPU and GPU have long moved off of the 3.3V rails to harness the 12V rail for DC-DC conversion in various VRM stages, down to <<2V. My main appreciation for ATX12VO (12 volts only) is the MB can choose to right size the 5V and 3.3V rails appropriately. M.2 slots are driven from 3.3V only (even if M.2 devices step it up or down for their specific uses). A board with 4 M.2 slots will have a different potential 3.3V power demand than a board with only 2 slots. Typically, a decent board will have 1 M.2 2230 A or E slot for WiFi, and 1-2 M.2 2280/22110 M (and rarely B) slots for M.2 storage. PCIe x16 lanes will have 9W of 3.3V, as part of their 75W total power (the remaining 66W is 12V). As noted earlier, 5V is heavily I/O driven. A board with 15 USB ports can expect to need more 5V than a stingy board with only 8 (both are accounting for front I/O headers). I'd rather the MB have to right-size the 3.3V and 5V rails, than forcing every PSU to include copious amounts of 3.3 and 5 just to cover every edge case. Sure, it's a tiny bit of potential efficiency. It's also passing a bit of cost from the PSU to the board itself. Sadly, it does seem ATX12VO's main impact will be lost. OEMs are going to continue with their custom PSUs with unique connectors and the DIY vendor + consumer market has largely turned their backs to this.
aidenn0 4y ago
Can you show me what you mean by the UPS style PSU? That setup sounds like it would be great for keeping my mini server up during power outages (Xeon-D also running off of a picoPSU).
- genewitch 4y ago
  sure, ASIN B00EAIG17E "DROK 110V 220V UPS Battery Backup Uninterruptible Switching Power Supply 12V 120W 110V-240V to 13.5V DC 50/60Hz with Battery Interface for Charging" When you remove mains power it switches over instantly enough that the computer doesn't notice. There's no serial port on it so the computer has no way of knowing that it's on battery - but it was also only $26 shipped. No wires or battery or anything. I happen to have a few of the trimpot breakouts specifically for setting voltages, so i just made sure that when the PC was powered it was getting the correct voltage without sagging below 12.2ish under load at the output terminal of the PSU. It also has a little trimpot on the board for adjusting the voltage. P.S. I'm not sure if Drok has a lot of knockoffs or not, i do know that i like that brand well enough, never had anything bought from them break in a weird way. I have slagged a few of their "waterproof" 24VDC boost converters, though!
MezzoDelCammin 4y ago
it's not "that" steep once You consider the form factor and the technology used. Generally the most You can get from a PSU this size would be those forementioned USB-C PD bricks. Those would these days get You at max about 100W for probably not less than 50-60USD (cheap Chinese models, more if branded). Multiply that 2.5x (250W instead of 100W) and suddenly You're pretty close to the price.

rektide 4y ago

> I wonder if it is possible to run more than one board off the same PSU. Absolutely. There's something I can't remember about signal lines that need to be set up, but yet, people have been running multiple computers off as single supply for a long long long time now. Also worth warning people ahead of time, it's hard to predict what kind of specific power consumption a motherboard will have. There's so many power rails going in. 3.3V, 5V, 12V, -3.3V... Making sure that each rail is adequately rated for additional motherboards can be a challenge. Ideally one would test each supply line, one by one, to try & figure things out, & compare against rated specs of the power supply. Intel's been pushing a new spec called ATX12VO, short for 12-volts-only, which does away with all the other rails & has the motherboard expect 12v. This would make it much easier to understand what power consumption is. I do seem to recall some of the new ATX specs (3.0?) also kind of expect power-consumers to declare how much power they expect to use, as a safety/planning feature, which could complicate this one easy-to-do hack (unless there's some way for the additional motherboard/motherboards to also declare their power draw). This might only be ATX3.0's new 12VHPWR connector, which works alongside PCIe 5.0-- not sure if it also impacts motherboards or not.

robocat 4y ago
> Making sure that each rail is adequately rated for additional motherboards can be a challenge Buy a cheap inline tester and leave it always in? Something like: https://www.google.co.nz/search?q=Power+Supply+Tester+Digital+LCD+20%2F24+Pin+PSU+ATX+BA4 https://www.google.co.nz/search?q=Power+Supply+Tester+Digita...
paulmd 4y ago
These days the 3.3v rail and -3.3v rail are practically vestigial (iirc the major consumer on those rails was floppy disk drives...) and 5V is mostly used to drive SSDs and USB devices. Almost everything runs off 12V these days - which is the whole point behind the 12VO standard, just make everything use 12V and step it down at the point-of-consumption for the handful of things that still need something else. So basically I wouldn't worry about motherboard compatibility due to 5v, 3.3v, and -3.3v rails - there just isn't much of anything still being done on those rails, and the things that do use it pretty much are the same across motherboards (because they're things that are plugged into the motherboard, not the motherboard itself).
- mschuster91 4y ago
  > and 5V is mostly used to drive SSDs and USB devices. The most important 5V rail is 5VSB - it powers wake-on-LAN and on some systems wake-via-bluetooth. The interesting question is, is it more efficient to always let 12V->5V regulators run for 5VSB or to use an extremely small separate regulator?
  - glowingly 4y ago
    To be fair, something is stepping it down from AC, and many modern PSUs step everything down from a common DC rail using DC-DC conversion (i.e, 12V, 5V, 3.3V, etc are all generated from a source DC voltage). Then things like the CPU and GPU have long moved off of the 3.3V rails to harness the 12V rail for DC-DC conversion in various VRM stages, down to <<2V. My main appreciation for ATX12VO (12 volts only) is the MB can choose to right size the 5V and 3.3V rails appropriately. M.2 slots are driven from 3.3V only (even if M.2 devices step it up or down for their specific uses). A board with 4 M.2 slots will have a different potential 3.3V power demand than a board with only 2 slots. Typically, a decent board will have 1 M.2 2230 A or E slot for WiFi, and 1-2 M.2 2280/22110 M (and rarely B) slots for M.2 storage. PCIe x16 lanes will have 9W of 3.3V, as part of their 75W total power (the remaining 66W is 12V). As noted earlier, 5V is heavily I/O driven. A board with 15 USB ports can expect to need more 5V than a stingy board with only 8 (both are accounting for front I/O headers). I'd rather the MB have to right-size the 3.3V and 5V rails, than forcing every PSU to include copious amounts of 3.3 and 5 just to cover every edge case. Sure, it's a tiny bit of potential efficiency. It's also passing a bit of cost from the PSU to the board itself. Sadly, it does seem ATX12VO's main impact will be lost. OEMs are going to continue with their custom PSUs with unique connectors and the DIY vendor + consumer market has largely turned their backs to this.

aidenn0 4y ago

Can you show me what you mean by the UPS style PSU? That setup sounds like it would be great for keeping my mini server up during power outages (Xeon-D also running off of a picoPSU).

genewitch 4y ago
sure, ASIN B00EAIG17E "DROK 110V 220V UPS Battery Backup Uninterruptible Switching Power Supply 12V 120W 110V-240V to 13.5V DC 50/60Hz with Battery Interface for Charging" When you remove mains power it switches over instantly enough that the computer doesn't notice. There's no serial port on it so the computer has no way of knowing that it's on battery - but it was also only $26 shipped. No wires or battery or anything. I happen to have a few of the trimpot breakouts specifically for setting voltages, so i just made sure that when the PC was powered it was getting the correct voltage without sagging below 12.2ish under load at the output terminal of the PSU. It also has a little trimpot on the board for adjusting the voltage. P.S. I'm not sure if Drok has a lot of knockoffs or not, i do know that i like that brand well enough, never had anything bought from them break in a weird way. I have slagged a few of their "waterproof" 24VDC boost converters, though!

MezzoDelCammin 4y ago

it's not "that" steep once You consider the form factor and the technology used. Generally the most You can get from a PSU this size would be those forementioned USB-C PD bricks. Those would these days get You at max about 100W for probably not less than 50-60USD (cheap Chinese models, more if branded). Multiply that 2.5x (250W instead of 100W) and suddenly You're pretty close to the price.