Originally posted by: Soldier
Originally posted by: FastEddie
The PCPC units put out 34/38A on the 12v rail....
That's part of my argument---you don't need 38a on the 12v rail for an Sli box. 28a to 34a will run any sli configuration you put together.
Your making a major mistake by equating SLi and lower power requirements. The power requirements of SLi based cards are no less on the power supply, they simply direct additional current through the PCI-E slot to handle the cards load. The cards still pull a lot of power, especialy in SLi. Not to mention all of the other components that still need to be powered such as drives, case fans, and overclcoked CPU's that still pull their full load of power regardless of slot type on a motherboard.
You still don't need 38a on the 12v rail. Dual 6800 Ultra's draw just under 9amps for the pair of them. If you couple that with a worst case scenerio (130nm FX53) that adds another 9amps to the task. That's 18amps between processor and graphics. The motherboard will draw about 4amps off the 12v rail (remainder is drawn off the 3.3v & 5v) which puts you at about 22a. The remainder of devices (drives, fans, pci, etc won't draw a total of 4amps off the 12v rail. That's 26a MAX (worst case possible), so with a 20% margin that brings your maximum amp draw (with the margin) just under 33a.
Note--a new 90nm FX55 draws about 3amps less that the FX53, which makes 34a a margin of over 30%. I mean, have a psu with a 38a rating on the 12v rail, but it's major overkill.