I recently helped my friend build a PC, and he's been facing some severe overheating problems that are leading to crashes. When we first set it up, his PC was idling around 60°C, which seemed high, but over the past month, it started idling at 78°C. It climbs even higher while gaming. We re-applied thermal paste today, checked for any leftover plastic bits from the assembly, and didn't find any major issues. After the thermal paste replacement, the idle temperature dropped to about 50°C, but he still experienced crashes while playing Destiny when temperatures hit 90°C. The AIO cooler is set to pull air from inside the case and push it out at the top, yet the case itself remains relatively cool. Here's his build list: https://pcpartpicker.com/list/Z9Bq8Q
2 Answers
It sounds like you've done quite a bit already! If you've double-checked that there's no plastic on the AIO cold plate, the thermal paste is applied correctly, and the pump is securely fastened to the motherboard, then it might be that the pump is actually malfunctioning and needs to be returned. It could be running but not effectively circulating coolant.
What are the RPM speeds of the AIO fans? If they spin normally but the temps are still high, it could be worth trying a different cooler altogether, like an air cooler. The Peerless Assassin is a solid choice for testing.
The AIO fans are running at about 2000 RPM when idle and ramp up to around 2900 RPM under load, so it seems like they should be fine.
We did verify all that today, and I made sure the thumb screws were tight enough — it seems to be set up like my own PC, so I'm at a loss.