Originally Posted by Cyclops
Hehe 850 for quad SLI. Oh well.
I know; the more fun you want to have, the more expensive it gets. lol
Here's my proof of 850W:
They only did 3-way SLi, but they measured the power draw individually: first with just one card, then with the 2nd, and finally with the 3rd. So this makes it easy to figure out what it would have been if they added a 4th. So here's what my finding is:
When they added the 2nd card, the power draw from the wall outlet went up by 166W. When they added the 3rd card, it went up by 176W. So I'll just assume that adding a 4th card would increase the power draw by about 185W. So here's my calculation based on that:
With three GTX 680s under full load in their system, their power supply pulled 649W from the wall outlet. Their CPU was idling, so we have to add about 150W for that. Adding a 4th GTX 680 would probably add another 185W to how much power the PSU is pulling from the wall outlet, bringing the total amount of power being pulled from the wall outlet to 984W. So, if the PSU is 85% efficient while pulling 984W from the wall outlet, then that would mean the system is pulling 836W from the PSU - but only if there is a full load on the GTX 680s and the CPU simultaneously.
If my finding is correct, then I would think that the HX750 would be stretched beyond its limits a little bit. It would probably work, but I don't know how long and it would probably get too hot. Although, if you are loading the 4 GTX 680s and your CPU is basically just idling (if you never have a simultaneous maximum load on both the CPU and the GTX 680s), then the HX750 would defintely be enough. I mean, adding about 185W to 649W only comes out to be 834W being pulled from the wall which comes out to being 708W being pulled from the PSU (if it's 85% efficient while pulling 834W from the wall).
Although still, I'd personally be unable to relax if I were trying to power such a setup with a quality-made 750W PSU of any kind.
Edited by TwoCables - 11/21/12 at 9:36pm