SLI PSU Question

[Orius]

Thinking of getting a second GTX 470 for an SLI setup but I am concerned about the amount of power I might need.

I have utilized the eXtreme power supply calculator to the best of my ability and it shows that with my current desktop setup I should run @ ~650 watts required with a 2X470 SLI setup, so I should be ok there.

Would OC under SLI be a possiblity with my current PSU or would that be asking way too much? How much headroom power is needed to be considered "safe."

My specs:
Mobo - ASUS P6X58D-e
CPU - i7930 @ 3.8GHZ (1.24 vcore)
Cooler - Xigmatek Dark Knight
PSU - Corsair HX750W
RAM - 6GB OCZ Gold
HDD - RealSSD C300 64GB (OS)
HDD - CaviarBlack 1TB Sata III (Storage)
EVGA GTX 470 Vanilla (OC'd 774/1800)
USB Peripherals - 5 or 6
Case - CoolMaster 690II

Thanks.

 

[N1GHTRA1N]

I think a 750w power supply would be pushing it for that setup. It might work but you'd be right on the edge.

 

[novadaemon]

I think you can pull it off. I run a similar setup and i actually upgraded to an OC'd gtx 480 on a 650w and the PSU doesnt even seem like it's struggling at all. As sloppy as this math is, 150w for the cpu + 215w for each card leaves just enough headroom for your other components.

 

[TwistedAegis]

I believe that PSU is rated for it and should be OK. I personally tend to give myself more headroom, but I do see quite a few people running just fine with a 750W, as long as it is a good quality unit. (thats what she said.)

 

[sabregen]

you should be fine on a single rail 750 with 470 SLI

 

[pug71]

OP- the fact you are using a quality 750w PSU and not some lower end unit will mean you will cruise along fine.

 

[Saabjock]

I think a 750w power supply would be pushing it for that setup. It might work but you'd be right on the edge.

Even a good 750w power supply will work for that SLI setup...with no issues. I did just that with a PCP&C Silencer 750. My specs were a 3.9GHz overclocked I7-920, GTX470SLI (Galaxy), 6GB DDR3-1333, two Pioneer DVD writers, 3x 7200rpm SATA 1TB Spinpoint drives and 2x SSD drives. I had an extremely stable system as proven by running Prime95, RTHDRIBL and futuremark benchmarks all at the same time. Never had one single crash or hiccup.

 

[DoubleTap]

I managed to put my 1000W Strider into thermal shutdown with 2 GTX480s running Furmark. No overclocking at all.

750 is probably enough as long as you don't overclock.

 

[Camph]

470s in SLI use ~580w under load, you have plenty of power

 

[Orius]

So the TLDR for this answer is:

YES SLI 2X470 is fine with 750W PSU BUT NO OC?


A follow up question. How much of a heat increase inside my case can I expect? Would it be advisable to ad 1 or 2 more fans to improve cooling? Or would a dedicated GPU cooler be a better/safer way to go?