Question GPU crashes at high load, except after running benchmark

Sep 16, 2019
My GPU crashes at high load, ranging from very low performance and stuttering to game crashes or even system crashes. This occurs unless I run Unigine Heaven Benchmark at Ultra settings with Normal tessellation beforehand, then everything after runs buttery smooth. Bit of a weird fix, not sure why this happens. Crashes also occur if I up tessellation in Unigine to Extreme.

I have performed a clean driver install using DDU, both before and after resetting Windows 10 to clear everything out. The problem persisted. I believe it may be an issue of an ageing PSU (see specs below) and as such am considering an upgrade to an EVGA SuperNOVA 750 P2. It may also be GPU problems, but it's only a year old so I doubt this is the case. Any feedback would be appreciated before I fork out for something which might not fix the issue. Cheers!

MoBo: Asus P8Z77-V ~6 years old
CPU: Intel i5-3570k overclocked to 4.3GHz ~6 years old
GPU: Zotac Nvidia GTX 1080ti Mini ~1 year old
RAM: 16GB @ 2400MHz <1 year old
PSU: Corsair CX750 ~6 years old
SSD: Samsung SSD 840 EVO 250GB ~6 years old

I bought the system in 2013 prebuilt with the CPU OC, and have since upgraded the GPU and RAM. All hardware drivers are up to date, and other than the CPU all hardware is at factory default settings, and I haven't changed the CPU OC from what it was when I bought it. SSD is in good condition according to Samsung Magician. I'm dual booting with Ubuntu on a separate hard drive but don't think that should affect anything. Windows and games both installed on the SSD.
Yes, it's very possible it's the PSU. After 6 years those PSU's are out of warranty, and losing efficiency and power output.

First thing i'd do is take off the OC on the CPU. If you are OC the GPU, take that off too.

A 1080ti OC and running at full pelt can draw as much as 300w depending on the GPU.

Make sure everything is at stock, and try again.

Getting a new PSU is a quick and mostly cost effective way of fixing issues like that. I'd recommend a good EVGA G2/G3 650w, or a Seasonic Focus Plus Gold. You don't really need a 750w PSU. 650w is enough, and allows some headroom.