My PC has worked normally since 2021, but recently both the CPU and GPU have started running much hotter than before. I've reapplied the CPU thermal paste, added another case fan, and even replaced the CPU cooler, but none of those changes helped. The CPU can reach around 80–90°C during a game while showing only about 40% usage, and it sits near 53°C at roughly 10% usage. The GPU idles around 55°C and usually reaches 65–75°C while gaming. The system has occasionally shut itself off, presumably because of overheating. I'm using an 11th-generation Intel Core i5-11400 and an NVIDIA GeForce RTX 3070 Ti, and I'm not sure whether the cause is hardware, software, or airflow.
2 Answers
Case airflow is worth checking, especially if the filters or heatsinks have collected dust, but opening the side panel and seeing no improvement makes the case less likely to be the root cause. I’d compare temperatures and clock speeds with a monitoring tool, check for unusual background load, and inspect BIOS settings for changed voltage or power behavior. If the cooler is mounted properly and the temperatures are still abnormally high, the motherboard’s fan control or CPU voltage settings may have changed.
The CPU appears to be the main problem here. A 90°C reading at only moderate reported usage isn’t typical if the cooler is working and mounted correctly. Since you’ve already changed the paste and cooler, check that the cooler is making firm, even contact with the CPU, that its fan is spinning at the expected speed, and that the CPU fan is connected to the correct motherboard header. Also check whether any background process is using CPU time even when the game’s reported usage looks low.
I tested it in a game and the CPU went over 90°C while the GPU stayed around 65–75°C, so the CPU does seem to be the bigger issue. It also reaches about 50°C even at low idle usage.
The case is an XPG Battlecruiser from 2021, and the temperatures stay about the same with the PC completely open, so airflow probably isn’t the only issue.