Fan noise increases when my laptop is idle or locked

When I lock my laptop (Ctrl+Alt+l) or let it run idle for a while, it starts making a lot of noise (also when I’m watching a movie) But when I touch my mouse and run top or KSysGuard, it almost immediately disappears. It does seem there has been some increased CPU load, but I’m unable to track down the cause. It’s almost as if a virus is using my CPU for something (I believed viruses didn’t exist on Linux) I’m getting really annoyed of this noise (which seems to be for no reason) Is the fan control not working correctly? I do have an optimus system with one NVIDIA GPU which is idle most of the time in case that matters.

the NVIDA chip is NOT at idle if you have not installed Bumblebee and the NVIDA-bumblebee package The default OS driver will run the NVIDA chip at full speed.

Since you did not mention Bumblebee I assume you have not installed it. Also you should not Install the normal NVIDIA driver. If you have be sure to fully remove it before installing the NVIDIA-bumblebee package. If you need instructions ask. It is easy to mess this Optimus thing up.

Also be sure that if you have set the NVIDIA repos active to remove or disable it since updates from there may break things.

I have bumblebee installed already. I did have a lot of issues with it because the openGL library path got messed up. Currently I can run programs on my NVIDIA chip using:
LD_LIBRARY_PATH=/usr/X11R6/lib64 optirun glxspheres

But which NVIDIA driver did you install? It simply does not work right with the normal NVIDIA driver you must use the nvidia-bumblebee driver and only that driver installing the regular driver and not removing it before installing the bumblebee version does not work either. The regular version must be completely removed before installing the bumblebee version. The fan problem is exactly what’s to be expected if you did not do it right. And it is very picky about doing it right. To make matters worse uninstalling NVIDA after installing sever versions on top of one another may not bring things back to day one. If me I’d reinstall the OS and do Bumblebee right since flounering around can leave things in unknown states. Also maybe drop NVIDIA a line and asking them to provide a real solution. Bumblebee is not official NVIDA it a kludge to make the normal NVIDIA driver work in Optimus

Aww, I see. Perhaps this is not the right place to ask, but is there any way to do a full re-install and backup/restore my entire OS (like including apache configs etc., I can also just write my /home to an external storage but I’d still have to reconfigure a lot of stuff and I’m not really looking forward to that) Thanks for your answer, I will re-install suse when I’ve got the time.

Never saw the point in backing up an OS. The configs yes. Most system configs are in /etc there are very few exceptions. You should strive to keep the system separate from the data.