Unneeded noise is mostly caused by not suitable pc parts mounting. In some cases this intorable noise is made up by metal screws. Best solutions for that problem is to use AAB Anti Vibration Rubber Screwsmore
The Anti-vibration Case Feet is designed to decouple a PC
case from the floor or substrate by absorbing vibrational
energy, and therefore helping to minimize noise generation
caused by vibrations.more