PC suddenly became very loud for no reason?

[raving]

I was using my PC as i normally do (no abnormal programs or new hardware) when suddenly it became very loud. Worryingly loud. So i turned my computer off and opened it up, the fans were full of dust so i cleaned them out and took the opportunity to apply new thermal paste. When i turned my PC back on (even before reaching the login screen) though it was still incredibly loud so i took the side off and from what i could tell it was the CPU fan.

Then randomly while search for a fix it stopped and returned to the ordinary near silent level of noise.

Any idea what may have happened? Is there anything i should be wary of?

Also the second it stopped it reminded me of when i'm processing very large videos, i don't do this often but the high level of noise then sudden seemingly permanent stop was very similar. Could a very intense program have been running in the background unnoticed. (just something that came to mind)

This isn't currently an issue but i'd like to hear what you believe it may have been. Thanks!

 

[electro_neanderthal]

It may have just been the fan working out any dust that collected in/near the bearing (if it even uses bearings). Windows also sometimes has one of its background processes (like superfetch) work hard for seemingly no reason. It doesn't seem like anything to be worried about unless it repeats regularly.

If it does repeat regularly, you can probably swap it for an existing case fan to see if it's the fan or the PC. But overall, it's just a fan. If it dies it's probably the cheapest thing you can replace, so I wouldn't be too worried; especially if the BIOS is set to give you a warning should the fan plugged into the CPU Fan header stop working.

 

[raving]

It may have just been the fan working out any dust that collected in/near the bearing (if it even uses bearings). Windows also sometimes has one of its background processes (like superfetch) work hard for seemingly no reason. It doesn't seem like anything to be worried about unless it repeats regularly.

If it does repeat regularly, you can probably swap it for an existing case fan to see if it's the fan or the PC. But overall, it's just a fan. If it dies it's probably the cheapest thing you can replace, so I wouldn't be too worried; especially if the BIOS is set to give you a warning should the fan plugged into the CPU Fan header stop working.

Thanks. Given it has returned to normal i figured it's probably not a big issue but i'll keep an eye on it.