Hi. In my current system I've got an 800w Tagan TG800-u33 powering dual 3.0ghz Xeon (Nocona) processors and an EVGA 8800 GTX Black Pearl. The Tagan handles this all fine (and the watercooling) but I'm planning to ditch the Xeons for a Core i7 920 (D0) with the intention of overclocking it. I've also got 4 7200 SATA drives.
Is my current Tagan sufficient to power this? Or do I need something else? My case will take two PSUs but what would be best split off on to a second PSU if nessecary?
Also, and it pains me to ask this, is my graphics card past it? It's been bottlenecked by my CPUs pretty much since I bought it..
The PSU has 6x 12v rails, supposedly 20A max each. But it apparently has a turbo switch, to combine the 6 rails together into a common rail with more amps. Am I going to need to do that, or is it enough to leave them separate?
I checked several references. You should not have any problems. Normally it is not necessary to switch to turbo mode unless your system is very close to the maximum load on the +12 volt rails.
An Intel Core i7 system with one video card will not require 800 watts. During a typical gaming session the total power consumption will be considerably less. The psu can easily power a system with two video cards operating in dual Crossfire or SLI mode. It would be different if you did some very serious overclocking and used multiple power hungry video cards.