Hey, sorry to hear about all these gliches, chickennoob.
I used to have a Leadtek 9800 GX2 and it worked fine with 7 64-bit in RC & RTM form. It was a fantastic card and could beat my GTX 285 in some cases. I kinda regret selling it now, to tell the truth.
It's not clear to me where the problem lies, but you might want to check some things:
- Are you sure that SLI is enabled in the driver? Check that it's enabled and staying enabled. Your card is performing like it has only one GPU, right?
- Make sure SLI mode is set to nvidia default
- The fan & temperature don't seem quite right. If the card is overheating, then it's quite likely that the hardware temperature protection will throttle down a core without any warning. The fan may be spinning, but can you feel air being blown out the back and is it warm?
- I would try to do Solaris17's suggestions to the letter; he's very knowledgeable
- Could you have malware on your system that's messing around with the card somehow? Not very likely I know, but cannot discount it, as I haven't seen how your system is set up for security eg hardware firewall, security patches, a/v installed etc etc
And finally, if you can, I strongly recommend at this stage that you get another hard disc and install the same OS on it, then patch it, install the video driver and your games/benchmark software and see how it runs. It could simply be that your current Windows installation is now FKD. Comparing with a fresh one will allow you to determine this absolutely and get a baseline on this.
Good luck and let us know how you get on.