my 3 6970s in my P8P67 Ws Revolution have given me many headaches as well. Sometimes Windows 7 64 bit will detect all 3, but 1 will have the exclamation point in Device Mgr. This only happens once if at all and only when I'm first installing the cards or switching back from my Nvidia gtx 560 ti SLI setup which is understandable. But what I do when it does it is move the cards around into different slots and it usually detects it. Also if you have an additional crossfire cable, try that. One of my CFX cables had an issue before and it would cause all sorts of artifacts, I'd touch it, and they'd disappear. I replaced it, and that was it.
One main thing is, are you supplying power to the additional molex connector by the cpu? That might help with TriFire. Also before I would RMA the board I would grab an old HD and try a fresh install of your OS first if you can.
I have literally been through every thing there possibly is to debug my Trifire issues as I was having a particularly annoying issue with battlefield bc2 where it would white screen if I didnt have my fans up @ 100% as well as all cards downclocked to 800mhz core, which didnt really hurt performance much at all.
If you're able to boot just fine with the 6990, but you cant with the 6970, you would definately need to RMA that 6970. Before you RMA anything, definately try downclocking to stock settings or even a little below.
ONE other thing I've experimented with with mixed results is adjusting my VCCIO voltages up to a max of 1.2v which did seem to help somewhat but I don't ever suggest messing with voltages because of the consequences of such actions, however I had pretty much had enough with it and was about to go back to normal Crossfire on my P67A-G45 board or just run my GTX 560 Ti SLI config on this WS Revo board which works impeccably.
Debugging hardware issues when running complex 'relatively' new tech like Tri-Fire with AMD's already somewhat buggy drivers is a task in itself and we all have our limits of patience. Who wants to reboot their PC for 6 hours when they could be gaming? Not I.
As far as the Crossfire drop down menu not letting you enable crossfire, I've had that happen multiple times. Most of the time it was a driver issue, such as a bad driver installation, buggy driver, etc. I would just 'properly' revert back to a previous driver revision and usually it would work fine.
Hopefully you get it sorted out. I researched this motherboard alot before I ordered it, and it was mostly because of all of its fancy features and relatively low price premium compared to similarly featured boards from other vendors. If I had to guess, I'd say NF200 isn't exactly 100% stable yet with AMD's drivers and I'll be switching back to my SLI setup on this board once I ship my 6970s off. There's nothing like getting a white screen when 10 seconds away from a 15k point game of battlefield ending and losing the points. Metro, Starcraft II, Heaven 2.5, etc all work fine though, but Battlefield BC2 is my fave and I will not stand for any white screen bs anymore
Anyways, perhaps I've strayed from your topic slightly but given the fact that we have the same setup nearly, I figured I could be of SOME help.
What I would do in your situation is
- Run the 6990 on its stock BIOS and drop all clocks on the 6970 to stock if they are OC'd
- Run the CPU/RAM/Etc 100% stock voltages/frequencies
- Grab an old IDE/SATA 20GB HDD and Format/Install Win 7 on it and test with that (I actually had NO issues whatsoever even with Battlefield after reinstalling Win 7 64 bit and the 11.4 catalyst driver)
If that doesn't work, make sure you have the extra molex power added to the mobo, play with the VCCIO voltage up to no higher than 1.2v, and also try running your memory @ +.05v over what you normally do. I had to do that to get my Revo board to POST at all when I first bought it.
There are SO many things to try I could write all day long, but good luck.