i see that this power supply has 6 12v rails http://www.newegg.com/Product/Produ... and by looking at the connectors i'd have to guess that 2 are for the cpu, 2 for video cards, and 2 for all the 4 pin molexes. am i correct? 64A on 6 rails means an incredibly weak 11A per rail right? or perhaps some of the power would be diverted from the unused rails to give higher max amperage?

Your link didn't work for me but it is my understanding that the latest thinking on powersupplies is that one 12v rail capable of delivering a large load is better than several rails delivering the same sum as the large rail can handle peaks that would overload smaller rails. Goin' Fishin' (Some day)

Yeah, it's got six independent rails as well as a turbo mode that combines the six rails into one. Your assumption that each of the six rails provides the same current (about 11 amps) may be flawed. The specs there don't say but each rail could have it's own maximum such that some max out at less than 11 and some at more than 11 amps. I don't think the rails will be 'borrowing' from each other unless the PSU is in turbo mode.

A PSU with a single +12v rail at high amperage is preferrable to one with mulitple +12v rails. That PSU has six +12v rails rated at 20A each...you would think that would add up to 120A, but it's only 64A total. It would be better to get a PSU with a single 64A rail (or thereabouts). Power Supply Myths Exposed! http://www.newegg.com/Product/Produ... http://www.newegg.com/Product/Produ...

Some high end graphics cards need 17/18A alone. Newegg.com has been clearing multi 12V rail PSUs for months. I think the manufacturers realized the weaknesses after a production run. Some are even well known brands.