Originally Posted by Chatassys
Guru3D made a review and they got 850W with 3-Sli GTX Titan and an overclocked processor with watercooling.
Since all those PSUs are already made with a little room to spare, any 1000W PSU will easily handle a 3Way. But if you want to be absolutely safe, buy a 1200W.
No need to go beyond that unless you plan on going 4Way...
850 will get you by at stock speeds. I'm running two oc titans with an oc 3770k. And the 850 is running at full load. Def won't be good for 3 OC titans. Besides power supplies are most efficient between 50-60 percent load so while a 1000w be enough for 3 Titans l, it will be running at 85-90 percent load, which is not good.
Never cheap out on a power supply. Is a good idea to get enough wattage to run at 50-60 percent load, that's why I suggest a 1500.
But yeah, a 1000w psu will get him by, just not as efficient as a 1500 will.