I bought an even faster and better computer last year, it was a 3.2 GHZ and it was twice as noisy, in January when it was cold out and cool in this room. It was very very fast but the noise was unbearable. I brought it back and got a slower computer so that the sound wouldn't be as loud.
Nothing is broken or dirty.
It just heats up very fast and becomes noisy when its summer time. 9 months a year its ok.