My PC's fans sometimes become noticeably louder, especially while I'm using it, but the noise is not constant. When I open Task Manager, the fans often quiet down immediately, or the system becomes quiet again after a few seconds. I'm concerned this could be a cryptocurrency miner or another background process hiding its activity. I scanned the computer with Malwarebytes, Kaspersky, and HitmanPro, but none found anything. During one episode, I opened Resource Monitor and the fans stayed loud long enough for me to check CPU usage, but I didn't notice anything unusual. What should I check to determine whether this is malware or simply a cooling or background-task issue?
2 Answers
Use a hardware monitor such as Libre Hardware Monitor with logging enabled. Check whether CPU or GPU usage, temperatures, or clock speeds increase when the fans get louder, even when you aren’t doing anything. A small background load may be normal, and a cooler that is dusty, poorly mounted, or using an aggressive fan curve can become audible from even modest activity.
A process that stops using resources when Task Manager opens can be a sign of malware designed to avoid detection, although the behavior alone doesn’t prove that. Check Task Manager’s Startup apps and installed programs, review scheduled tasks and running processes, and run an offline or boot-time security scan rather than relying only on normal scans. Resource Monitor staying active during the noise makes a simple anti-monitoring trick less certain, so also investigate temperatures and fan behavior.
The noise is louder than usual but not extreme, and Resource Monitor stayed open while it happened. I’ll check logged CPU and GPU temperatures before assuming it’s a miner.
Could a miner still be responsible if the CPU usage only rises a little?