Need some ideas - 8800 GTX extremely slow

I just got my hands on an 8800 gtx by MSI (used - Guy says it worked fine for him). Unfortunately it is only about half as fast as my 8600 GT OC by MSI. 3dMark06 - 3078 as opposed to 6034. Some said it was my Power Supply, which was an OCZ 700 Watt Game X Stream. While I doubted this, I bit the bullet and put in an 850 Watt Silverstone with 70A on a single rail. Nothing. Still extremely slow. Uninstalled drivers, reinstalled latest drivers, tried Driver Cleaner Pro, nothing.

Temps idle on GPU at 44C with fan at 75%. GPU-Z identifies all aspects of card fine and it is running at its default speed of 610Mhz/2000Mhz.

I am at a loss as to where to go. Anyone have an idea of what to try?

Comp Specs:

DFI Lan Party NF590-SLI M2R/G
AMD 5000+ BE 2.6 @ 3.2Ghz (Water Cooled)
2 GB OCZ PC6400 4-4-4-12
2 74Gb WD Raptors in Raid 0
1 DVD Writer
Winblows Vista 32 bit

Thanks.

Yep, tried the 169.25, 169.44, and the beta drivers 174.74? i think that's the version. Also, both PCIE 6 pin connectors are plugged in. I haven't recieved any messages about the card being underpowered. Which reminds me... where in the world is the Nvidia Power Sentinel everyone is talking about lately? Automatically installed? Hiding somewhere? Needs to be installed seperately?

Thanks again.

Best bet is some thing is wrong the the graphic drivers. Also some thing could be running in the background. Also are both cards installed (8600 and the 8800) or just the 8800?

Just the 8800 gtx is installed. I've run Windows Vista Experience index and it is rated at 5.6 for this card. So was my 8600 gt.

3dMark06 is getting 7 - 17 FPS with all the benchmarks. Haven't tried any games. Figured it would be pointless at the moment.

I suspect driver problems too. Even after running driver cleaner, I had a time when the card wasn't recognized by windows as an 8800gtx, but would only detect as a Standard VGA Adapter. It took about 3 uninstall/reinstalls of the drivers to get it to be recognized properly.

As much as I hate to do it... I may have to end up formatting and reinstalling...

One question for you 8800 Card owners... Is your "Change Settings" button available for changing hardware acceleration? Because mine isn't. It is greyed out and unclickable. So I can't change video hardware acceleration.

Thanks.

Hmmm, GPU-Z says that it is running at 16x in the PCI-E slot. I'll have to check and see what the bios says, and check the voltage.

Anyone have an answer on the Hardware acceleration question above? That one is driving me crazy.

Thanks everyone for your help.

Well, nevermind. I would like to think that an Asus Crosshair would have some tweek options in the bios, but no... No Options for voltage or changing the pcix lanes. GPU=z says it's running at 16x. But dont know how to check if it's for sure staying there when under load.

Wow. Wish my problem was that simple. But GPU-Z says I'm running a full x16 PCI Lanes and the Core Clock and Memory Clock are running at full speed too... sigh. I'll probably try a format, just as soon as I find out whether or not missing the Hardware acceleration option is normal in Vista or not.

to inglburt or anyone else i raised the voltage up just 0.1 volts to the pci express overvoltage control in the bios may be called some thing different with other makes/types of bios