PC fan randomly revving up

[Lupu]

Every 10 minutes(not sure if its exact but its always around that) my case fan will rev up very loudly for about 2 seconds. This happens all the time even when idle. I've cleaned it all out and thats not seemed to make a difference. As far as I can tell from looking at task manager the fan spike is not related to increases in CPU usage. Anyone got any ideas or what I can try? Thanks

[emosun]

can check if a bios update specifically mentions any issues regarding it