Okay so i am building a new rig and it is the first time i have done it, it is through PCSpecialist so i am not physically building it but i am choosin all the parts... I dont believe the whole system is of any importance but please let me know if it would help you. I have a choice between... 2 HD's both are a terabyte in size, the first is 7,200rpm and has a 16mb Cache, the other is a western digital performance caviar green drive? It has a 64mb cache and intellipower? But it doesnt give a range... I would be pulled towards the WD HD because of the cache being 4x as big, but i dont like the sound of this intellipower, how much difference does the size of the cache make? I dont know what this means at all i am only giving you the facts i know, boths a 3gb/s which is the fastes my mb will handle so that is fine and both are within £8 of each other so price doesnt come into this, Thanks in advance for any help/advice