I just finished building my core i7 system and am waiting for a Corsair 850tx to come, but to make sure everything was working i put an old coomax v-400 400 watt psu that i had in my old system. I installed vista x64 and tried it out but it feels like somthing is holding it back, also my hdtune bench was terrible. it dosent feel much faster than my really old AMD 3500+ system. Could my old 400 watt be causing the terrible performance or is it mabey a hardware issue? Thanks.