I don't know, but usually they are all one size and compress themselves.

In the unverified new version, I added the steps to replace the thermal paste. The loud noise might be a bad fan bearing. Download HWMonitor to see the CPU temps. If its over 50 idling, and 70 doing any work, you might want to try new thermal paste, or clean or replace the fans and paste. The chip to the right of the CPU is usually the GPU, marked nVidia if you have the Quadro Model, and there is a chip under the CPU which I do not know the function of.