Bitcoin Forum

I have been reading the forum for some time and also have been mining for a while.  I have one rig with four 6870s and another with two 5830s.  I decided to add a 6990 to my machine (personal use machine not a mining rig) but when I installed it I only see one of the GPUs for mining.  I am running Win7 with the latest Catalyst drivers (11.6 I think) and using poclbm for mining.

Has anyone run into this before?  After searching online for answers I have only seen one post describing the same situation and they claimed that updated drivers fixed their issue.  I wouldn't have purchased a 6990 if I was building another rig but bang for buck since I had my existing system with an open PCI-E slot it was a no brainer but right now it is only performing 340MH/s (I haven't overclocked it yet since I need to get the other GPU working first) which isn't much better than my 5830's that overclocked are doing 300-310MH/s and they only cost $109 compared to the 6990 at $700. 

I see both GPUs in AMD Overdrive but in poclbm there is only the one.

Any suggestions are much appreciated.

Happened to me once on first boot when I set up a dual 6990 rig on Windows.

Switch PCI-e lanes with another card, wait until the microcode drivers (not AMD Catalyst)
are auto-installed by the OS.

After that you can put it in the old slot.

Then you should see both cores and any other GPU's on that system.
http://i56.tinypic.com/sou2yg.jpg

If you still fail to see all cores it could indicate the motherboard is not capable of delivering sufficient power to all GPU's on the board.

Thanks for the suggestion... I will try that tomorrow morning when I get a chance to work on it and report results for anyone with the same problem or just for interest sake.

The motherboard should be sufficient (MSI 890FXA-GD70) and I took the the other cards out to test it by itself just in case.

If this doesn't work I will move it to ubuntu and see if that solves the problem.

Any other tricks or tests are welcome as I will not be able to attack this problem until tomorrow and I might as well have a list of things to try.

Thanks again.

Go into Catalyst Center and go to the Hardware tab. What does it say for the 6990?

I fixed this by using a dummy plug on the dvi connector.

It does say that one of the adapters is disabled.  I have my monitor plugged into the mini-displayport with the mini-displayport-dvi adapter and I have a dummy plug in the actual dvi adapter on the card.  I have moved the connection to my monitor around the four different mini-display ports but it remains disabled in ccc.

Thanks for the help... not sure what is different but I uninstalled the drivers, rebooted, re-installed the drivers and now ccc reports them linked.

Wish I had a better explanation for those who run into this in the future but I do not.

Now to see how much overclocking I can do.

Thanks again.

 I had simmilar issues. My overall problem was that the stupid card wasnt booting because i didnt have a monitor plugged into it(long story short)