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The cables are bigger than the PSU. Has anyone ever experimented with putting edge connectors on a motherboard PCB for power? And edge connector for PCI and mem

The cables are bigger than the PSU. Has anyone ever experimented with putting edge connectors on a motherboard PCB for power? And edge connector for PCI and memory and m.2? In this way you could build out a very flat PC with commodity parts, since all the components would be parallel to each other and the motherboard.

jonah-archive 4y ago
The SGI O2 was built like this (power & all bus connections were off an edge connector), some good pics of the mobo at: https://bukosek.si/hardware/collection/sgi-o2.html#pics https://bukosek.si/hardware/collection/sgi-o2.html#pics
kayson 4y ago
Dell PowerEdge Servers do this. And they have 1.1kW PSUs!!
- mrb 4y ago
  Indeed. Edge connectors are common on servers with hot-swappable PSUs.
- unwind 4y ago
  Wow, didn't know they thought it was important enough of a feature to put it in the name of the product. :)
c_o_n_v_e_x 4y ago
You should look at CRPS form factor power supplies, they have the edge connector you are referring to. ATX12VO also addresses the large legacy ATX connector.
jabl 4y ago
Wasn't there some upcoming PSU spec that dropped the 5 and 3.3V rails leaving only 12V? What happened to that? Edit: Yes, the "ATX12VO" spec.
- rocqua 4y ago
  Yes, but it seems unlikely to hit consumer markets soon. It is mostly interesting for OEMs apparently. I hope I am wrong though.
  - vladvasiliu 4y ago
    Aren't OEMs already able to do pretty much what they want? I have a desktop HP that has a standard-sized PSU but has a weird connector that only plugs into the motherboard. The drives are powered from a separate connector that also plugs into the motherboard. And the PSU - MB connector is much smaller than standard ATX.
    - rocqua 4y ago
      HP can control the full stack. MB and PSU at the same time. But smaller OEMs might want to not have to manufacture their own totally custom components. So it makes sense for them to standardize. If not for interchangeablity then to ensure you can sell your custom parts to other OEMs.
- bombcar 4y ago
  I know we don't need 5v for spinning drives anymore, but what voltage does the CPU want to see? If it's not 12V aren't we just moving the voltage drop equipment onto the motherboard?
  - heretogetout 4y ago
    Consumer CPUs these days are at around 1.4 to 1.5 volts. Not sure about server, but it's probably close.
  - hnuser123456 4y ago
    CPUs are around 1-1.2v. However, they can occasionally pull 100-200+W. Moving 200W at 1V means 200A. Resistive losses scale proportional to amperage at constant voltage, and inversely proportional to voltage at constant power. 200A needs a LOT of copper to not get blistering hot, the amount you would find in all the traces connecting a CPU to the VRMs on the motherboard, probably around 4 ounces just to carry the power a few inches. 200W at 12V is 16.7A, which can be shuttled much longer distances with less material at the same efficiency, in the ~foot long cable between the PSU and motherboard. Additionally, pluggable connectors are high resistance spots in the circuit unless they make very good contact, and susceptible to overheat and melt when carrying too much current.
kraftman 4y ago
You can get 90 degree adapters for the motherboard power connector and PCI, and low profile ram. the issue then is getting a low profile heatsink for the CPU. There are waterblocks but not many with edge ports. There are also boards like this that have the RAM mounted flat, a lower profile set of ports on the back, and take in 19v DC: https://www.asrockind.com/en-gb/IMB-193 https://www.asrockind.com/en-gb/IMB-193
- javajosh 4y ago
  >the issue then is getting a low profile heatsink for the CPU You'd have to make something custom, but I think it would be much simpler than typical heat sinks. With air cooling, the vertical placement would be ideal, since convection will tend to suck cool air from the bottom and release it on the top. (I think the iMac does/did this). Even for water cooling, it would be simpler with far fewer turns in the pipe. Plus, I just like the idea of laying everything out flat instead of the weird 3-D origami that is modern PC design.

jonah-archive 4y ago

The SGI O2 was built like this (power & all bus connections were off an edge connector), some good pics of the mobo at: https://bukosek.si/hardware/collection/sgi-o2.html#pics https://bukosek.si/hardware/collection/sgi-o2.html#pics

kayson 4y ago

Dell PowerEdge Servers do this. And they have 1.1kW PSUs!!

mrb 4y ago
Indeed. Edge connectors are common on servers with hot-swappable PSUs.
unwind 4y ago
Wow, didn't know they thought it was important enough of a feature to put it in the name of the product. :)

c_o_n_v_e_x 4y ago

You should look at CRPS form factor power supplies, they have the edge connector you are referring to. ATX12VO also addresses the large legacy ATX connector.

jabl 4y ago

Wasn't there some upcoming PSU spec that dropped the 5 and 3.3V rails leaving only 12V? What happened to that? Edit: Yes, the "ATX12VO" spec.

rocqua 4y ago
Yes, but it seems unlikely to hit consumer markets soon. It is mostly interesting for OEMs apparently. I hope I am wrong though.
- vladvasiliu 4y ago
  Aren't OEMs already able to do pretty much what they want? I have a desktop HP that has a standard-sized PSU but has a weird connector that only plugs into the motherboard. The drives are powered from a separate connector that also plugs into the motherboard. And the PSU - MB connector is much smaller than standard ATX.
  - rocqua 4y ago
    HP can control the full stack. MB and PSU at the same time. But smaller OEMs might want to not have to manufacture their own totally custom components. So it makes sense for them to standardize. If not for interchangeablity then to ensure you can sell your custom parts to other OEMs.
bombcar 4y ago
I know we don't need 5v for spinning drives anymore, but what voltage does the CPU want to see? If it's not 12V aren't we just moving the voltage drop equipment onto the motherboard?
- heretogetout 4y ago
  Consumer CPUs these days are at around 1.4 to 1.5 volts. Not sure about server, but it's probably close.
- hnuser123456 4y ago
  CPUs are around 1-1.2v. However, they can occasionally pull 100-200+W. Moving 200W at 1V means 200A. Resistive losses scale proportional to amperage at constant voltage, and inversely proportional to voltage at constant power. 200A needs a LOT of copper to not get blistering hot, the amount you would find in all the traces connecting a CPU to the VRMs on the motherboard, probably around 4 ounces just to carry the power a few inches. 200W at 12V is 16.7A, which can be shuttled much longer distances with less material at the same efficiency, in the ~foot long cable between the PSU and motherboard. Additionally, pluggable connectors are high resistance spots in the circuit unless they make very good contact, and susceptible to overheat and melt when carrying too much current.

kraftman 4y ago

You can get 90 degree adapters for the motherboard power connector and PCI, and low profile ram. the issue then is getting a low profile heatsink for the CPU. There are waterblocks but not many with edge ports. There are also boards like this that have the RAM mounted flat, a lower profile set of ports on the back, and take in 19v DC: https://www.asrockind.com/en-gb/IMB-193 https://www.asrockind.com/en-gb/IMB-193

javajosh 4y ago
>the issue then is getting a low profile heatsink for the CPU You'd have to make something custom, but I think it would be much simpler than typical heat sinks. With air cooling, the vertical placement would be ideal, since convection will tend to suck cool air from the bottom and release it on the top. (I think the iMac does/did this). Even for water cooling, it would be simpler with far fewer turns in the pipe. Plus, I just like the idea of laying everything out flat instead of the weird 3-D origami that is modern PC design.