[0-4] Cayman ALWAYS fails verification, regardless of card or slot

[Fuzzy]

I have 5 cards hooked up to one machine right now. When I go to start all the cards up, the fifth card "[0-4] Cayman" always fails verification.

Disconnecting either the 2nd, 3rd, 4th or 5th card gets rid of the problem and the remaining 4 cards mine perfectly fine, meaning all the slots/cable/cards are ok, but adding a fifth card will make "[0-4] Cayman" ALWAYS fail verification, even when it's the only card mining and all other cards are stopped.

I'm using GUIminer 082011

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[DeathAndTaxes]

I have 5 cards hooked up to one machine right now. When I go to start all the cards up, the fifth card "[0-4] Cayman" always fails verification.

Disconnecting either the 2nd, 3rd, 4th or 5th card gets rid of the problem and the remaining 4 cards mine perfectly fine, meaning all the slots/cable/cards are ok, but adding a fifth card will make "[0-4] Cayman" ALWAYS fail verification, even when it's the only card mining and all other cards are stopped.

I'm using GUIminer 082011

What driver version, what OS?

The older drivers had problem w/ more than 4 GPU in Windows.

[Fuzzy]

11.9 resolves the Verification problem, but now I'm getting the Split Hashrate issue.

[Fuzzy]

11.10 either BSODs, crashed the VPU driver or GUI Miner

Installing Win7 x64 to see if anything helps.

Gonna try CGminer afterwards.

[grubles]

You can't have more than 4 gpus in Windows.

[DeathAndTaxes]

You can't have more than 4 gpus in Windows.

Yes you can.  I am running 8 right now.  The older drivers were limited to 4.  I am not sure which version lifted that cap to 8 but it was a while ago... 11.5? 11.6?

[cablepair]

have to tried to ditch guiminer and switch to cgminer?

it is much better at handling multiple gpus

[cablepair]

yeah it matters a lot.

32 bit windows sucks at handling multiple gpu setups