I meant PSU, not system. And I've heard Windows Vista x64 can be a memory and power hog....is that a truth or a rumor? Plus, I need enough power for these parts:
Radeon 3870 x2
AMD Athlon 6400+
DFI LANPARTY DK 790FX-M2RS
4gb DDR2 800
500 gb Hard drive
20x Optical