Power draw of 2 5870's vs 1 5970?

[Cablesaurus]

I'm trying to determine if I have enough of a PSU on one machine to rock an extra 5870.

I know it can run 2 5970's, Corsair 850TX.

I'm running 1 5970 and 1 5870 in that box currently, should that be enough power to run another 5870? (Which would essentially equal 2 5970's?)

[rezin777]

It's 80% efficient so you have 680W to use. To be safe lets say the 5970 is using 302W and the 5870s are 195W (both may actually be lower, especially with memory underclock). So, about 692W from the cards alone. I would say no.

[Tannke]

5970 (around 245 Watts) is more efficient than 2x 5870 (like 376W)   that's without overclocking...

(245+375)*1,20 (+20% electricity wasted)    thats 744W plus other power eaters like CPU, fans... etc

So depends on your system, if you have high-end CPU, RAM... etc. that PSU will scream "F*** you leave me alone"

[Littleshop]

My 900mhz clocked dual 5870 system with a sempron 140 CPU draws 600w at the wall as measured by a kill-a-watt.

[zoro]

i would say yes if the currents from 12v lines are enouph. as for the PSU efficiency i always though that the naming watts are the real
watts that the user can use and not the watts that are drawn from the plug!

[rezin777]

as for the PSU efficiency i always though that the naming watts are the real watts that the user can use and not the watts that are drawn from the plug!

I honestly don't know. And when I don't know something, I assume the worst case scenario so I'm not left empty handed.

[zoro]

from my experience,
i have used 2x5970 with 700w thermaltake modular. kill-a-watt shows 640 watts. the rig is mining for a week now. no problems!
i am also using a 780w tagan with a 5970 and 2x5850. kill-a-watt shows 650 watts, no problems either
i don't know how long these configurations are going to last