Alright so I have this crappy stock fan that came with my computer and at full speed you can hear it throughout my entire room. I'm looking to replace it with one of these 80mm fans as I have a small case and don't need anything bigger. http://www.amazon.com/Cooler-Master-Slim-80mm-Standard/...
So if I get an 80mm fan could I replace it? My fan measured 3 inches on the dime, which isn't exactly 80mm if I'm correct. I measured a whole side from top to bottom. This is my first time dealing with a computers fans so I'm new to it, thanks in advance for any help
Are you talking about the cpu cooler/fan assembly, or a discrete case fan?
Regardless, any 80mm fan needs to spin at high rpm's to generate any meaningful airflow. 92mm fans are not much better.
High rpm's are the primary contributor to noise.
If you are talking cpu cooler, se if you can't install a $30 cooler like the cm hyper212 which has a slow turning 120mm fan.
Replacing the actual fan on the heatsink wont help much with the noise issues, to do so you would need to get a whole new heatsink/fan setup. The Coolermaster Hyper 212+ or 212 evo are one of the best bets in air cooling for cpus, very quiet, very effective. The pin connectors will also hook up identical to the stock fan you have there.