Everything effects it... some games or benchmark tests stress one area more than another... some need memory bandwidth, some need GPU power, and some are more CPU dependant. Pretty much everything will have an effect on performance. For example... just switching to an nForce2 motherboard from an KT400 based motherboard, my 3DMark score increased by 400 points (if I remember correctly) Overclocking my CPU from 1833 Mhz to 2210 gave me about another 500-600 points... overclocking my video card gave me almost another 1000 points.