Power supplies, single and multi-rail and high wattage GPU

Dave Burton · 29 Jun 2022 at 13:20

Ok. After some recent discussion and disappointing info around certain brands of PSU, I pulled the trigger on the Corsair HX1000, which arrived today. For the first time, I was provided with a single/dual rail option which, after doing some reading, basically either gives me the full ampage (around 90A) on all 12V circuits with single, or 40Amp caps on the rails with multiple selected. I have an rtx 3080 Gaming OC, which after some investigating can have a max wattage of around 560W (note this is full on stress testing, not "normal" use). Doing some quick maths, 560/12 works out at around 47Amps max, I'd therefore not be able to user multi-rail 12V @40A monitoring as if the card hit peak the OCP would kick in, does that sound about right?

Sorry for the wall of text, input and/or confirmation would be appreciated

DB

Dave Burton · 29 Jun 2022 at 15:41

EsaT said:
Having multiple current limited wire groups is definitely far better for safety on that size PSU.
Would need extremely low resistance from short to trigger overcurrent protection, if normal allowed is 90A.

But you need to make sure graphics card's power cables are on separate current limiters.
PSU's user manual should tell about that.

Oddly, the PSU manual gives next to no information about what the single/multi option does but based on the reply below it would make sense. As the GPU has 2 cables, and therefore 2 connection ports, each one would be 40A so effectively 80A (depending on how power is distributed on the card, naturally). Can only give it a go...

Dave Burton · 29 Jun 2022 at 15:42

Tetras said:
As far as I know, all it does is restrict what's available on one cable and that graphics card has two 8 pins, doesn't it?.

Yeah, I'm new to it, the manual seems to indicate this is the case, I'm going to be brave and give it a go, what could possibly go wrong...

Dave Burton · 4 Jul 2022 at 10:00

Just popping back in to say the new PSU fixed the random shut-offs, been going strong with multi-rail set for 6 days with zero incidents, whereas before I'd have numerous daily shut-offs! Huzzah!

Dave Burton · 4 Jul 2022 at 11:59

Major774 said:
What PSU size was you running before.

I am just wondering as I needed to upgrade my PSU as well, transient spikes with the 3080 FE meant my old PSU was struggling.

Hiya, I was running a Seasonic Focus+ Gold rated at 850W but was experiencing random power cut-outs due to OPC being twitchy with these units, I did a lot of digging and found it was a common complaint with users of RTX3 series cards and the cards spiking randomly and cutting the PSU out. My new Corsair HX1000 is doing the job just fine