Hi everyone, I've had this PC for almost six years, with a few upgrades along the way. Over the past two weeks, it has started randomly restarting or shutting down during games, including some that aren't particularly demanding. My Ryzen 7 5800X reaches at least 90°C while gaming and sits around 80°C on the desktop. The room has also been unusually warm lately, around 28–29°C. I suspect the CPU cooler may be inadequate, but I'm not sure whether the temperatures are causing the shutdowns or if another component—such as the power supply, RAM, or graphics card—could be responsible. What should I check first?
4 Answers
Those temperatures are definitely worth addressing, so clean the cooler, check that it’s mounted firmly, and replace the thermal paste if it’s old. A stronger cooler, such as a dual-tower air cooler, would also be a sensible upgrade. However, high CPU temperatures don’t automatically explain random power-offs; the full system specifications are needed, especially the graphics card and power supply. CPUs often reduce their speed when they get hot rather than instantly shutting down.
Please list the CPU, graphics card, motherboard, power supply, and RAM. Sudden restarts are often related to power delivery, unstable memory, or overclocking, and the temperatures alone don’t prove that heat is the cause. You can also check Windows Event Viewer under Windows Logs and look for errors around the time of each restart.
Use a hardware monitor or OCCT to watch CPU, GPU, and motherboard temperatures under load. Also test with any CPU, GPU, or RAM overclocks and memory profiles disabled. Unstable RAM or an aggressive overclock can cause sudden restarts, so testing everything at stock settings can help narrow it down.
Start with the cooling because around 80°C while idle is unusually high. Remove dust, confirm the fan is spinning, reseat the cooler, and apply fresh thermal paste. If the cooler has failed or isn’t making proper contact, that could explain the behavior, although it’s still worth checking the rest of the system afterward.

Thanks, I’ll gather the complete specifications and check the cooler after work.