Other How to reduce cable clutter to a minimum

[EdZ]

The GPU should not be drawing power, but the motherboard will be, and potentially any connected devices (e.g. standby charge for USB). If the PcioPSU is providing 5V and 3.3V, then the 12V supply will also need to be active rather than idle to supply it in order for the PC to boot. ATX PSUs have pretty standardised behaviour for idling and low power modes, but a 'normal' 12V PSU may not behave in the manner we're used to.

 

[ChainedHope]

I have a some ideas i'd like to bounce off you guys, sorry if it was mentioned but I just skimmed the thread when looking for a way to fit a system configuration i've been playing with into a smaller scratch case.

For the 24 pin - Splice the 160XT pico psu to use the power/ground plane of the SFX psu and rewire the 4pin cpu connector to an 8pin by piggy backing off the molex connector. Essentially making both connectors come from the 2 wires from the psu.

For Sata: use mSata/M.2 to completely drop the sata power/data cabling. Alternatively you can piggy back off the 160XT extra molex header if your drives are close enough to the 24pin header on the motherboard for SSDs.

For GPU: Use a card that can use motherboard power (750ti) or single 6 pin. Seems simple, but if you are using a 2 way setup or need 2 6-pins, you can split a single 8 pin from the SFX psu into 2 6-pin connectors from the single line. You shouldn't overclock with this, but it will in most cases be enough power to run at stock for most cards (mileage may vary, I've done it for 2-way nanos just to test and stability was good).

And of course custom wiring for everything will be a must to keep cables in check. This all assumes you have a decent psu with high efficiency. Dirty power will kill this.

 

[iFreilicht]

That's close to what I was imagining in the first post. I think it should work, but you'll need to make sure that the PSU is single rail, or - if it isn't - has sufficient power for each component on the respective rail you're connecting it to.

 

[Hahutzy]

I had a similar thought when I was looking at the PCIE ribbon extension I was using the other day.

Is there a world where we could just have connectors where the other end is a socket for a universal internal-connect cable that is thin and round?

For example, male 24-pin connector onto mITX board, male 24-pin connector into Flex/SFX/SFXL psu.
Then USB-like cable that connects to sockets in the male 24-pin connectors.

Male pcie onto mITX board, female pcie onto GPU
Same USB-like cable connects to sockets in the connectors.

 

[ChainedHope]

I had a similar thought when I was looking at the PCIE ribbon extension I was using the other day.

Is there a world where we could just have connectors where the other end is a socket for a universal internal-connect cable that is thin and round?

For example, male 24-pin connector onto mITX board, male 24-pin connector into Flex/SFX/SFXL psu.
Then USB-like cable that connects to sockets in the male 24-pin connectors.

Male pcie onto mITX board, female pcie onto GPU
Same USB-like cable connects to sockets in the connectors.

I might be able to come up with something in this regard. I'll make some designs and push them out as open source, maybe then a manufacturer or individual with the resources can try it out or work from it.

That's close to what I was imagining in the first post. I think it should work, but you'll need to make sure that the PSU is single rail, or - if it isn't - has sufficient power for each component on the respective rail you're connecting it to.

I think im going to try it when I get the chance, it will make a feature in my ideas thread if I get it working well enough.

 

[BirdofPrey]

Well there is that OCuLink thing that the PCIe Consortium has been working on, but I haven't heard anything about it recently, and version 1 is only 4 links, so you'd need 4 of them for a graphics card assuming link ganging were supported.
Still cables like that along with power cord would be much appreciated as an alternative to ribbon risers.

As for power, the big thing is just using a smaller connector design. Mini-fit connector are still rather sizable when there's a bunch of cables, and wire gauge and amperage restrictions require multiple voltage and ground lines, though the biggest problem with the ATX connector is having multiple voltages, and is the reason thin-mini ITX just convert voltages on the motherboard.
====
I posted earlier an idea for a Main PSU in the case and a PicoPSU like PSU on the motherboard socket.
Since it is controlled by the motherboard still and produces 12VDC, a system like that could easily power GPUs and scale with the number of cards you have. It also still allows for the power brick setup PicoPSUs use now. I also figured, the EPS can be provided by a passthrough off the mobo PSU rather than a second cable bundle.

Other peripherals can be powered by the motherboard PSU, or as an option, make drive backplanes that accept 12V only and convert the other voltages (granted they tend to be little used) on the backplane; additionally, being a backplane, it can accept mini-SAS connectors to connect up to 4 drives back to the motherboard per cable, so that's extra wire savings.

 

[zhl146]

Well I tried passing through the PS_ON from my pico 160XT to a SF600 corsair SFX PSU and I was not able to turn the PSU on . I literally just stuck a wire into the PS_ON on the pico and crimped an ATX pin to the PS_ON on the SFX. Should it be more complicated than this?

EDIT: I read earlier in the thread something about 5V for standby. Do I need to run an additional wire for 5V so the mobo gets standby power before this will work?

 

[jeshikat]

EDIT: I read earlier in the thread something about 5V for standby. Do I need to run an additional wire for 5V so the mobo gets standby power before this will work?

Right, the motherboard needs 5VSB. The PS_ON wire has a 5V signal from the power supply and when the motherboard pulls it down (or you short it ground with a paperclip) it tells the PSU to turn on. But the mobo needs power for that circuit to work.

 

[zhl146]

Right, the motherboard needs 5VSB. The PS_ON wire has a 5V signal from the power supply and when the motherboard pulls it down (or you short it ground with a paperclip) it tells the PSU to turn on. But the mobo needs power for that circuit to work.

Roger that. Will try that next time I open the machine up! Unfortunate that I need to run 2 wires though

 

[iFreilicht]

Unfortunate that I need to run 2 wires though

Still much better than 24, don't you think?

 

[zhl146]

Still much better than 24, don't you think?

Well we'll find out!

Do you (or anyone else) know what max amperage I should expect on the 5V or PS_ON lines? I want to know because I would like to be able to get away with using 22AWG wire for those two additional runs if I don't need to carry much current.

 

[ChainedHope]

Well we'll find out!

Do you (or anyone else) know what max amperage I should expect on the 5V or PS_ON lines? I want to know because I would like to be able to get away with using 22AWG wire for those two additional runs if I don't need to carry much current.

dont quote me but i think they only go to 2 mA

 

[jeshikat]

If I'm reading the ATX 2.2 spec correctly, it looks like 1.6mA. So yeah, 22 gauge should be plenty

Edit: For PS_ON

 

[iFreilicht]

For 5VUSB, you can get higher power draws, some PSUs can deliver 2A there, so you might want to step it up if you like to charge multiple phones on your PC while it is turned off.