CF 6870, or 6950?

antiv6

Limp Gawd
Joined
Mar 11, 2007
Messages
297
Kind of wanting more power(and dual 23" 1920x1080 displays :D) and can't decide what I should do.

Would adding an additional 6870 be the best bet? The same one I have can be had for ~$180 AR on newegg.

Or, would buying a card similar to a 6950 yield better results? A 6950 can be had for around $30 more. :(

Additionally, would my old school Corsair 620w power supply be able to reliably power the new setup?

Thanks guys.
 
6870's in Crossfire run rings around a single 6950. For your setup and since you already own a 6870, Crossfire is the way Id go.
 
I bought a second 6870, and it was a massive boost. I would also vote for the Crossfire..
 
Was looking thru the Anand Bench after I posted and a pair of 6870's even whoops up on a GTX580! Not too shabby. Of course youll have to deal with the few compatibility and driver issues that seem to plague CrossfireX but they seem to be getting fewer and far between.
 
Nice guys.

Isn't it possible to add a 6950 with a 6870 and run CF with that?

Also, is a 620w PSU enough to run everything?
 
I dont think so. With Crossfire you dont have to use the same cards, but they have to be from the same family. For example, you can use a 5850 and 5870 but not 5850 and 5770. And when you do use two different cards, they scale down to the slowest so a 5850 and 5870 would work like a pair of 5870's.

As for power, a quality PSU like that Corsair will be enough for a pair of 6870's but it will be cutting it close. If memory serves, a pair of 6870's will have total system draw bumping up against 500 but Im not 100% on that. If you afford a 750 or bigger power supply, it might not be a bad idea to upgrade for the headroom. Power supplies run cooler, quieter, more efficiently and last longer when kept in the 40-60% range.
 
I dont think so. With Crossfire you dont have to use the same cards, but they have to be from the same family. For example, you can use a 5850 and 5870 but not 5850 and 5770. And when you do use two different cards, they scale down to the slowest so a 5850 and 5870 would work like a pair of 5870's.

As for power, a quality PSU like that Corsair will be enough for a pair of 6870's but it will be cutting it close. If memory serves, a pair of 6870's will have total system draw bumping up against 500 but Im not 100% on that. If you afford a 750 or bigger power supply, it might not be a bad idea to upgrade for the headroom. Power supplies run cooler, quieter, more efficiently and last longer when kept in the 40-60% range.

Hmm, well, my old setup(8800GTX, C2D e6420, etc) ran well with it...

The power drain on a 6870 is 151w max. So:
151 x 2 = 302 watts total draw.

The power draw for an 8800 GTX was 315 watts max.

I'm also running more power efficient CPU and RAM.

Guess I'll grab the GPU asap, then upgrade the PSU in the near future.

Thanks for all the help guys!
 
The anandtech link posted above clearly shows that total system power draw with CF 6870s in their tests is only 415w in Crysis and 481w in Furmark, so I don't see why you would need a bigger PSU...

(unless you want to furmark all day)

I believe most of their tests are with a 1366 i7, so going to an SB chip, the overall number could be 50 watts lower, putting you in a great spot.
 
The anandtech link posted above clearly shows that total system power draw with CF 6870s in their tests is only 415w in Crysis and 481w in Furmark, so I don't see why you would need a bigger PSU...

(unless you want to furmark all day)

I believe most of their tests are with a 1366 i7, so going to an SB chip, the overall number could be 50 watts lower, putting you in a great spot.

This. My 5.0GHz 2500k with CF HD6950 2GB cards hits about 500w at the wall under a Prime95/Furmark load. The Seasonic X650 Gold that powers it all is more than up to the task.
 
Agreed, 620 watts will cover it but its still not a bad idea to get a bigger PSU so youre not running it at 85% capacity. It's not a necessity but does mean more efficiency and longer term reliability from your PSU if you run it closer to 50%.
 
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