Firstly, hello! Long time poster @ Hexus forums, but my first time posting here So here's the issue, it's a 2nd hand PC with the following spec: i7-6700K @ stock MSI Z170-A Gaming M5 Corsair 120mm AIO Sapphire Pulse Vega 56 8Gb 4x4Gb Corsair Dominator 2800Mhz Aerocool Project 7 850W 80+ Platinum PSU NZXT H440 case with 3x 120mm fans fitted in front as intake 256Gb Samsung 960 Evo NVME + 1Tb HDD I've ran a combined Prime 95 + MSI Kombustor run for 10-15 minutes, no issues. I've loaded up 'The Finals' (UE5 game) and ran around for 15-20 minutes without any issues, but as soon as I load up Fortnite it'll crash within 2 minutes with a hard PC reset, boot up and load back to desktop. Given it's stable in other games / high loads, I don't think it's the core components or heat (CPU was about 70C / GPU was 67C in The Finals). It could be a RAM issue if Fortnite is utilising it more, I will run at 2400Mhz and see if that stabilises it For reference the GPU wasn't posting initially, but a strip down and clean, repaste and new thermal pads brought it back to life and apart from this specifc issue with Fortnite I've had no other issues with it so far, and it's been stable when 100% fully loaded. It could be the GPU I suppose and the way Fortnite is stressing it, but my gut reaction is that it is stable now as I would expect it to falter in other loads if it was having issues. Any thoughts appreciated
Grab MemTest86, create a USB stick with it on (there's a video guide on the page I've linked should you need it) and UEFI boot it to test your RAM. It'll take a number of hours.