Power supply for a three video cards

[Gstar Nova]

Have spent a hour or more looking for the correct size power supply when i add a additional 7970 video card a total of 3, hoping to add a few more years to my existing rig. This is what I have at present               

cpu intel    i7 3820                     cpu- corsair h100..........................................................   as you can see I have a Corsair 850w that's been fine till now but with the additiona video card plus I plan                             

m.board    P9x79                       2- heatkillers full gpu                                                        to add a Oculus Rift next year I'm thinking a larger power supply is needed. Problem is using the different .                           

GPU AMD 2-7970                      coverage~ copper                                                            power supply calculators I came across there is a wide difference from 1000 to 1800 watts.

c drive ssd 520 plextor               aquacomputer airplex 420                                                Please give me a better idea what wattage will be necessay for peak usage. Thanks

raid vertex~126 gb                     external radiator                                                

d drive 2 tb seagate                   D5 pump                                                

g drive 2 tb seagate                   xspc pvc 1/2" id tubing                             

power corsair 850HX                  3 aercool shark 140 mm fans

monitors 3 lg ips 235v 23"          3 silverstone ap141 140x25 mm fans

monitor stand for 3 monitors      3 120 mm case fans

lg dvd RW

R.black widow ultimate

R. ouroboros

trackir v5 // 32 g corsair pro ram

T.Beach seven head phones 

seitek x pro 52      

[Kermit]

that layout tho

[rtpb5642]

WAT

 

U wont have enough VRAM in 3 years

[AlwaysFSX]

You know PCPartPicker is a thing, right?

[GlassBomb]

I would really just consider switching up the 7970's for something more modern. Adding a third 7970 will NOT improve graphics performance in games all that much, sadly.

 

Look into selling the 7970's for maybe $150 a piece, and then use that money towards a single graphics card in the $450+ range. Maybe even slightly higher, considering that you will have even more spare money, since you won't have to upgrade the PSU.

 

If you do that, then something like a 390x, Fury (non-x), GTX 980, or hell, maybe even a 980ti might even be within your budget.