Well I not too sure about that yuh know trini. There are other things to consider in these PSUs than I think most ppl realise. The cooling of the PSU, active/passive PFC, detachable connectors, overload/overvoltage protection, effeciency and the absolute maximum power or sustainable power. Alot of ppl see 500W and thing great, 500W normal, when in fact that may refer to 350-400W running 500 peak at x # of hours etc. Also that overvoltage/overload is a real necessity in T&T with T&T and all. PFC also is desirable to be active. The size of the cooling solution will affect the air flow in ur case and/or its ability to dissipate all the heat generated by teh PSU. The size will also affect the noise levels. I honest would cosider having dual psu vs. single LARGE. As it stands I just last night came to the sad realization that my thermaltake 480W was unable to power my 4400+ and it's by NO means low on specs... I think it's just getting on in age, but still I trust it over the 550W generic that I have my rig on temporarily. I've seen MANY rigs need over 400W, far less for SLI and Xfire rigs. This dual PSU is a good idea imho.