Multi rail 12V into the same GPU?

WalkerYYJ · January 31, 2019

Hey all,

Have a strange project where I need to run a 2080TI from a 1U server PSU.
Looking at using an IStarUSA TC-1U70PD8 700W http://www.istarusa.com/en/xeal/products.php?model=TC-1U70PD8

It has 4x 12V rails each rated at 16A max. Its a super compact build so I am going to have to chop the lines and re-crimp new Molex Minifit-Jr plugs anyway. How bad of an idea is it to bridge some of these buses together to supply the GPU?

I'm open to using another PSU, but again it needs to be 1U and have enough "Skookum" to run a 2080TI along with whatever the fanciest of the i9s would pull.

Thanks

mariushm · January 31, 2019

Just open the PSU and look on the pcb, you should see the 12v wires grouped and soldered to areas called 12V1 ,12v2 etc etc

Use one rail for each 8pin pci-e connector (16a x 12v = 192w), so your video card will be powered by two rails, one rail for 24pin + sata+molex , one rail for cpu.

If you don't overclock, 200w should be enough for the cpu.

2080ti peaks at around 260 watts, so that's around 40-50w through the slot and the rest through the extra connectors, so you won't hit the rail oc thresholds with ~ 100w per pci-e 8 pin connector.

It would be better if you'd use a single rail psu, should be able to find a 500-600w server psu with around the same dimensions.