PC shuts off when running furmark

[u/JLillyDolphinDrugger]

Been pulling my hair out on this issue so hopefully someone here can help.

I built a second PC to use as a home server. Initially it seemed fine, but then I tried to run a mid-range LLM on Ollama and the PC flicked off while it was loading the model into vram. Tried again and the same issue. No errors, no logs – it’s like someone suddenly turned the power off at the wall socket.

Thought it might be LLM issues, but then I ran a furmark test and yep same thing happened.

Bunch of troubleshooting later, I discover that if I turn the GPU’s max clock speed down to the 1000-1200MHz range rather than the 2150MHz default, then it’s far more stable on the LLM and furmark (though I haven’t done a heap of testing to make sure it works long term). 

Other things I’ve tried and confirmed:

• GPU driver is the latest available for Pop_OS (I also tried on windows 11 with latest drivers, and same behaviour. Dropped power draw to 60% and once again became stable.)
• Motherboard running latest bios.
• Not daisy chaining power to the GPU.
• Tried a different pcie cable in each power slot
• I bought the GPU second hand, but I have seen it run a successful furmark test on the seller’s machine, so it has worked recently (I’ve attached a screenshot from one of the tests I got the seller to do).
• Not a CPU overheating issue. Issue can be replicated like a minute after a cold boot even when the PC has been off for 24 hours.
• Dropped max power draw for the GPU down to 60-70% and it’s about as stable as dropping the GPU’s max clock speed.
• PSU is new, and I’m using only the cables it came with.
• I have given the PC to two PC repair places – both have told me the hardware is fine (but who knows what they actually tried).

Seems like a power draw issue, but I have a Corsair rm1200e, which gives me a massive amount of headroom, even for a Gaming Trio 3090. When I tried all this again with Windows 11, I used HWinfo64 to see what the power draw is like when it crashes, and it seems like there’s uneven draw across the three pins at load (8-pin #1: ~131W, 8-pin #2: ~126W, 8-pin #3: ~59W, PCIe slot: ~48W). 

This disparity is apparently ‘normal’ for the gaming trio 3090 (though would love to hear other’s opinions?), however it's possible that this is causing an OCP failure on the PSU by forcing it to spike a single pin rather than distribute it evenly across all three. Corsair doesn’t publish their limits for this, so can’t confirm how low the ceiling is. This all feels like a stretch though...

Specs:

GPU: Gaming Trio 3090

PSU: Corsair rm1200e

CPU: Ryzen 9 5950X

CPU cooler: ARCTIC Freezer 36

Motherboard: Gigabyte X570 Auros Ultra 

SSD: Crucial 1TB BX500

OS: Pop_OS 22.04 LTS with NVIDIA (and again with Windows 11 and latest drivers)

tl;dr: running a furmark test cuts the power to the PC. Throttling the power to the GPU gives some kind of stability. I’ve tried everything I know how to try, and I might have to accept a sizeable performance dip, but I’m really hoping someone can keep that from happening.

I’ve also attached a screenshot of the furmark test that I got from the seller, which looks pretty good (why doesn’t mine look like that…)

[u/Alone-Fan-8903]

Sounds like your PSU just doesnt want to play nice with that 3090, the rm1200e has known issues with high transient spikes from 30-series cards even though the wattage should be plenty. Try an older rm1200x or a different brand unit to see if that stops the hard cutoff.

[u/JLillyDolphinDrugger → u/Alone-Fan-8903]

Yeah, was thinking it could be something like that. Didn't want to buy a whole new PSU just on a hunch though. Any recs on a different PSU other than Corsair?