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6850 crossfire - possible PSU problem.

post #1 of 7
Thread Starter 
Hello all,

Long time anon lurker here. I would like to begin by saying thanks to all helpful peoples in here!

I bought x2 Gigabyte 6850's thats powered by a Cooler Master Silent Pro 700w.
With both cards connected and running i get freezes combined with a shutdown whenever i start a application. In some rare cases i can run a benchmark or play but with extremely horrible performance. We're talking 5 fps TOPS. Ive tried different drivers and so on but nothing helps.

So i have begin thinking maybe its the PSU thats causing this. But 700w is more than enough for my system. Im no guru when it comes to PSU but a single 12v rail with 50a shouldn't be a problem..

What do you guys/gals think?

MB: GA-790XTA-UD4
CPU: Phenom x4 965 BE
PSU: Cooler Master Silent Pro 700w.
post #2 of 7
Have you tried using only 1 card and seeing how it performs? If there is an improvement try the other card. This way you can rule out if there is a n issue with either one of the cards.

If they both work okay on there own, I'd suggest it's an issue with the PSU, but don't quote me on this

Good luck
 
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The Hoover
(14 items)
 
 
CPUMotherboardGraphicsRAM
2500k P8P67 EVO XFX 6870 2GB Corsair Vengeance LP White 
Hard DriveOptical DriveCoolingOS
Western Digital Caviar Green 1TB BluRay Hyper 212 EVO Windows 7 Ultimate 64bit 
MonitorPowerCaseMouse
Asus G245HQ Corsair 700 Corsair 800D R.A.T 5 
Audio
Corsair HS-1 
CPUMotherboardGraphicsRAM
Phenom II 550 M4A785TDV-EVO XFX 6870  4GB Corsair XMS3 
Hard DriveOptical DriveCoolingOS
1TB WD Caviar Black LG DVD+RW hyper 212+ Windows 7 Ultimate 64bit 
PowerCase
550w OCZ Fatality AeroCool: AeroEngine Plus 
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post #3 of 7
Yeah, you shouldn't be seeing power issues. Try the cards separately, one may be faulty.
post #4 of 7
Thread Starter 
Quote:
Originally Posted by BlueTac View Post
Have you tried using only 1 card and seeing how it performs? If there is an improvement try the other card. This way you can rule out if there is a n issue with either one of the cards.

If they both work okay on there own, I'd suggest it's an issue with the PSU, but don't quote me on this

Good luck
Quote:
Originally Posted by Phaedrus2129 View Post
Yeah, you shouldn't be seeing power issues. Try the cards separately, one may be faulty.

Yeah i have tried both cards alone and they work perfectly. Its just together they crash, with or without crossfire-bridge.
post #5 of 7
Could be a problem with the second pcie 2.0 slot on the motherboard
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post #6 of 7
Try to put the card in the second PCI-E slot on the motherboard and see if it still acts up.

Edit: Ninjad ^
    
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post #7 of 7
Thread Starter 
Quote:
Originally Posted by serp777 View Post
Could be a problem with the second pcie 2.0 slot on the motherboard
Quote:
Originally Posted by Markus View Post
Try to put the card in the second PCI-E slot on the motherboard and see if it still acts up.

Edit: Ninjad ^
Hi!

I tested the second slot and tried it in Vantage. The card performed worse than the 16x one, pretty much half fps. But i had some sound-driver problems while doing it so might have been that. It didn't crash though so its not broken i guess. Now i tried both cards again and had 1-4 fps in Vantage. And the computer hung up and booted when i was flipping between sensors in GPU-Z. The cards doesn't seem to go full load.. in my logs they are at 100 cpu clock most of the time, sometimes a bit higher, but never full.




I just tested it again and got some horrible results..

PCIE x16 12.5k gpu points
PCIE x8 2.5k gpu points

This seems really odd to me.. It behaves like this in crossfire too.. but i haven't crashed yet with a single in that slot. Guess this is whats causing all my headache. I had a PCIEx asus xonar DS in that slot previously but never encountered any problem. Can i fix this somehow? Or do you guys think the slot is totallly screwed?

I now realize im in the wrong forum right now for this kinda error..
Edited by vietnow - 12/22/10 at 7:05am
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