
Originally Posted by
Drdeath
You cannot use a PSU calculator cause every PSU has maximum amp rating on a rail. You need to see how many amps are on your rail(s). 6970's put out a max of 24 amps x 3(tri fire)= 72 amps that would be 3 cards. Add in the CPU and other hardware and you can run a heck of a lot more. If you load the rails over 90% the PSU IMO can have a short life The GPU's do not run 24 amps all the time so the 72 amps are max which is should never hit but always be on the safe side when running high $ of hardware........ I loaded one of the rails on my Corsair HX1000 and bingo, poof. To be safe with 3 6970's I would go with a high quality 1200W PSU just to be safe. IMO, the PSU is the least place to skimp and cut it close.
Your going to run 2 cards(crossfire) so the GPU's alone would be 48 amps...... How many amps on your rail(s) of your PSU?
Edit: I see 70 AMPS, on your corsair 850W you are good to go........ Your cards will never draw 48 amps unless your overclocked, overvolted and running the crap out of it...........