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Crossfire 6850s

Biggrich76

Limp Gawd
Joined
Mar 16, 2005
Messages
411
I'm looking to get a second 6850 and set up Crossfire soon. What is the minimum PSU size needed?

I have a Corsair HX-620 right now, and I'm assuming that's too small.

Thanks in advance.
 
Your 620 should be fine. The 6850s really don't use that much power overall. I'm running 2 6850s off a Seasonic x650 gold with no issues.
 
should be fine.
use a 750w with oc 2500k and crossfire oc never had any issues
those psu are solid performers
 
So I ordered the 2nd card listed here, which is the same card I had ordered from Newegg in December 2010. However (not sure if this has any bearing), the new card has 2 power connectors on the side of the card. But the old card has only a single connector on the end of the card so I'm assuming there was a new revision.

After hooking everything up, I ran some games and benchmarks but am getting pretty meh results. My 3dMark 11 scores are in the 6600 range which it says is low for my configuration.

I tried uninstalling/cleaning/reinstalling the ATI drivers, but that did not seem to help. GPU-Z shows both cards, but when running BF:BC2 the 2nd GPU never goes above 30% load, while the 1st GPU is at 99% load.

I have the Crossfire bridge installed, and the cards are in the respective x16 slots as the mobo manual states. I also downloaded and installed the most recent Crossfire profiles from ATI. If anyone has any suggestions to help improve the performance, I would greatly appreciate it.
 
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Umm... pretty sure I've NEVER seen a 6850 with 2 power connectors on it. That is odd. I would make sure they are clocking the same. However, at 6600, you are getting similar results to what I got, so no worries there.
 
I run Crossfire 6850s on a HX520 and my CPU is overclocked. Has not been a problem.
 
I did some more testing last night with FRAPS on BF:BC2 and I was getting around 110-115 FPS with Crossfire enabled vs. 55-60 without it, so it seems to be working.

However, there was a couple times playing MP last night that the PC froze and I had to do a hard reset. Hopefully it does not become a common occurrence.

Thanks for the replies!
 
That sounds like some pretty darn good results there. Seems like everything is working fine:) Enjoy the setup man!
 
Seems about right. That stupid 3Dmark11 always says yours scores are low because if you're drivers aren't their approved ones it compares them to overclocked scores. My 6950's get 7100-7200 on my PhenomII x6 system bone stock. You're fine.
 
I did some more testing last night with FRAPS on BF:BC2 and I was getting around 110-115 FPS with Crossfire enabled vs. 55-60 without it, so it seems to be working.

However, there was a couple times playing MP last night that the PC froze and I had to do a hard reset. Hopefully it does not become a common occurrence.

Thanks for the replies!

lucky...

my 6870's are broke in CF in BF:BC2 i get negative scaling. :(
 
using profile?

yep, nothing works, even reinstalled windows a few times with diff drivers all they way back to 10.6

i get 40-70fps with crossfire enabled and random stutter lockups.

with crossfire dissabled i get 70-120fps
 
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