Computer fan really loud, fluctuates, why?

[badass88gt]

I just replaced the motherboard and added a bunch of memory, the computer works good, but now the fan is whacked out. It will be quiet, then it gets real loud, then it quiets down again, the whole time the computer is powered on but just sitting idle. What is causing this? Thanks-Dan

[SSDude]

Probably a bearing starting to fail. Is it the power supply fan, processor fan or an axillary ventilation fan? Either way time for a new fan. Their cheap.

[badass88gt]

Its the case fan, it only started since I changed motherboards. It is actually changing speeds, not just a bad bearing sound.

[GTSLOW]

Your new motherboard might have a built in fan controller, unless its really iradic.