A second GeForce 9800 GTX installed is another ballgame though; on this system it requires you to have a 750 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total) at least 45 Amps available on the 12 volts rails.
I have 72A on all 4 Rails at 18A each, Right?
So am I good?
Also.
have a wattage monitor keeping a close eye on power consumption during our entire test-session. This device will register the maximum wattage pulled from the wall power outlet. You are not looking at the power consumption of the graphics card, but the consumption of the entire PC. We had a total system wattage peak at roughly 420 Watts with two 9800 GTX cards installed, which is quite a lot.
So that mean I need a Wall outlet right?
Ahh.
Check this out.
My PSU is 87% Efficient
Now At guru3d.com I found a PSU almost Exactly the same as mine.
They hooked up 2 GTX 295's in Quad SLI and a QX9770 OC'ed to 3.6GHz .