When I'm using software that uses a lot of cpu I can hear my fan start blowing out air harder. The fan fluctuates from high power to low power consistently. Even when my computer is doing nothing I can still hear the fan. I don't remember it being this loud when I first bought it. I've read that it may be a heat sink failure and I found some on ebay but I don't want to spend money unless I'm 100% sure that's the problem. Any information would be very helpful.
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It should be fine!
Download speedfan or realtemp to monitor your system temperatures. If they are getting too high, then you should replace the fan. If the temps are fine, and you can deal with the noise, then you dont' need to worry about it.