How many 6970's per 1500W PS

[NLA]

You can probably just barely fit 5 6970's comfortably with a 1500W PS if you flash the BIOS on all the cards so that the mem is at something low, like 150-300MHz, and don't overvolt the cards at all. Lowering the mem clock significantly reduces power consumption (and heat levels for GPU!) for me without hindering performance in the slightest, so I recommend it.

[Unacceptable]

I have them overclocked to 950-960 and ram set at 240
fans running at 100%

one of the reasons i want to watercool them is to get them quiet.

Are you sure everyone is talking about the same thing here?

My MSI Reference 6970s can NOT hit 950mhz stable without overvolting, and their stock clock is like, 880 IIRC. They can't even hit 920mhz at stock voltage. I get a solid 400mh/s at 910mhz.

Also, downclocking the memory below 300mhz usually always causes hard-lock. How in the hell did you manage to get it down to 240?

I have 2 XFX CNFC 6970's (crossfired for gaming)@ 935/1375,PCS @ +20 (fan @ 85%,temp 70-73c with 3 80mm helper fans)& get 425 mhs from each.When OC'ed like that my whole rig uses 720 watts(using Kingwin 800 watt).I'm not OC'in anymore till I upgrade my PSU to 1000 watt or more.

No luck for me either with downclocking mem so I left it @ stock

I would think 1500 watts would be cutting it too close for 5 of these,escpecially if OC'ed.

[cicada]

Totally suprised by the power draw of these things..  425mh/s for what seems to be 275W+..  the +20% must be increasing voltage to hit those marks.

[MadHacker]

i think everybody is right about adding another 6970 beeing not a good idea.

however now i'm wondering if i can move one of my 5830 cards onto it instead.
that it might have enough power for.
perhaps even 2 of them?

[cicada]

I think one should be fine - heavily OCd it should be shy of 200W.  Two 5830s will definitely draw more than a single 6970 though, I wouldn't push it

[MadHacker]

I think one should be fine - heavily OCd it should be shy of 200W.  Two 5830s will definitely draw more than a single 6970 though, I wouldn't push it

thanks...
I should be setting that up tomorrow or sunday