Problems using two XFX Radeon HD6870 Graphics Cards...

Right, I have an unusual problem here... and also apologise for the lengthy discription, but I though, the more I add the better.

This is my spec, just to help you out a bit

ASROCK 990fx Extreme 3 Mobo
FX8120 CPU> Asus AXE square Cooler
16gb Ram
2 XFX Radeon HD6870 GFX Xfire with Gelid Icy Vision Coolers
900W PSU
1TB 7200RPM HDD
OCZ Synapse Cache 64GB SSD
DVD/RW samsung
Windows 7 64x Ultimate


I am running 2 monitors using a DVI port and a mini Display port, and I have a HDMI cable connected to the TV, they all run on extended desktop in this formation


[ TV ].......[MAIN MONITOR].......[SECOND MONITOR]

The setup works perfect, and I have all screens connected to the Top graphics card, or the 1st PCIe Slot.

Connected via Crossfire bridge

a second HD6870 , connected in to the 2nd PCIe Slot. This doesnt have any displays connected into it.



Here is the problem, When I first started the setup, it worked great, both devices recognised in windows device manager, displayed both cards in the display adapters list.
I also have GPU observer gadgets on the WIN7 desktop, one gadget for each card, both worked fine, showed correct temperatures etc


A day or two ago, after shutting down and restarting, I noticed my gpu observer gadget for one of ther cards read " GPU not found" so I checked my device manager... it was correct, not even showing in there... so I restarted the comp 2 or 3 times... until it finally re appeared... fine.. so I left it, it runs perfectly, crossfire works, temperatures are great, so, last night, I shut my computer down.... turn on today.. not there again, and wont come back.


I have tried each card alone, in both slots, using both sets of pcie connectors, they work fine. but together, they are very temperamental.

Im running out of ideas now... and looking for some help. I have literally tried everything. and lets not forget, the drivers. Ive tried un installing and re installing. no luck..... Id say Im a few more trys away from a WIN7 clean wipe... haha

thanks for looking guys

Just shutdown pc.... turned it back on.... and it works again

It REALLY is confusing me this.... Drivers checked and up to date in catalyst and in windows.... now both gpu temps working again..

Just played modern Warfare 3 for half hour...... game ends to go back to the lobby.... The whole computer freezed... so i left it, come back about 20 mins later after food, to find the comp rebooted, and now.. guess what.... only one GFX card working...

Im not too sure what it was, but now its ok again :s very confusing...

Turned out to be a driver issue.... working perfectly now. Thanks anyway guys.