6990 + 5970

[EPiSKiNG]

I've been spending way too much time trying to get this rig running stable... Reinstalled windows 7 x64 with 6990 installed, put on 11.5 catalyst and 2.4 sdk, restarted, mining fine.  Then I installed the 5970 and booted up with monitors connected to each card, boots fine, guiminer detects all 4 cores, and I started mining... After about 2 hours, the computer shuts down... heat on all cores and vcc/voltage controllers are showing ok temps (less than 100c).  I don't have a crossfire cable installed, and I have acooler master pro gold 1000 watt psu that is less than 2 months old.  I used to have 2 5970 installed in this same computer and it was rock solid even with moderate to high overclocking...

Any ideas guys?  Your help is extremely appreciated.

-EP

[1713985278]

1713985278

[1713985278]

1713985278

[1713985278]

1713985278

[1713985278]

1713985278

[dingus]

Try getting another PSU and testing that out...it could be your PSU is faulty and can't handle both of those cards at once.

[EPiSKiNG]

When buying a new psu, I'm looking at the Corsair 1200 watt, which has a single 12v rail at 108amps, or Antec has a new 1200 watt that has 8 12v rails, each at 30 amps.. I've heard it's better to have a single rail.... thoughts?

-EP

[Inaba]

You should be able to drive those two cards with that PSU... depending on the age of the PSU and room temp.  You are probably right at the limit of the thing though, depending on the other components in your system.

[clonedone]

up the fans to make ur gpus under 80C not 100 try that. if it dosent work, remove 11.5 cata, then reinstall 11.5 cata with both cards already on with crossfire

[marcus_of_augustus]

100 C is way too hot for those cores, you may have damaged them already. Crank the fans to keep temps. not much above 70 degrees C.

[allinvain]

100 C is way too hot for those cores, you may have damaged them already. Crank the fans to keep temps. not much above 70 degrees C.

I think he was referring to the VRM temps being 100 or below. If his cores were at 100 they'd be throttling themselves if I'm not mistaken.

Umm, did a calcuation and if you have a reference 5970 and reference 6990 (not overclocked) the total power  draw for both cards should be 600W. That does not factor in other power usage by the system. So I'd say your power supply should be up to the job as long as it's not faulty in some way. When you used the dual 5970 did you also use the same power supply?

Also keep one or all the monitors on and see if there is a blue screen (drivers crash) before it shuts down. Try also leaving the 6990 in the non overclocked position (it's got a switch on it - or it should).