I figured I would add yet another datapoint:
Asus Crosshair III Formula (790FX chipset)
Dual GTX280s
Windows 7 x64
HAL mod
191.07 drivers
-Works great
Upgraded to 195.xx WHQL drivers, no SLI. Decided to run with only 1 card, video would drop out completely (black screen) and lock the system. Uninstalled the extra GTX280, still 195.xx WHQL drivers and would still get black screens and lockups. Uninstalled 195.xx WHQL drivers, reinstalled 191.07s, system is stable, runs great.
Obviously they are not only doing extra checks for 195.xx WHQL drivers, but they are also causing problems if they do find things patched. I did not undo the HAL mod to see if 195.xx WHQL drivers would work or not without it.
I was originally running a Foxconn Destroyer (nvidia 780a chipset) with a 9950BE along with the dual GTX280s. But, I decided to setup a machine for my oldest daughter that would server double-duty as a server, so the motherboard/processor/memory and a 9800GTX I had sitting around went into her setup and I upgraded to a Asus Crosshair III Formula with a X4 955 and DDR3 RAM because I got a hell of a deal on everything, but really the major reason I decided it was doable was because of the SLI hack due to my dual GTX280s.
The new setup runs flawlessly with the 191.07 drivers and I really hope you guys figure out how to get even newer ones running.
I just can't believe that nVidia doesn't offer a consumer level 'upgrade' where we as consumers could buy a nVidia SLI certificate/certification for our motherboards. Hell, I believe the cost I heard for x58 motherboard producers was $5 per board for certifying them, so why not offer the same to consumers for $7-10 for whatever system they want to run under SLI?
Now I do understand that some system may not be 100% compatible, and nVidia probably doesn't want to get into the testing/certification market because of that, but why not offer it on a 'development' basis for those of use that want to 'take the risk'? (well, outside of the OBVIOUS, and probably biggest reason they don't, and that being all the idiots that can barely put there system together, let alone configure a system to run a setup it wasn't intended/certified for, as I am certian they would be inundated with support calls/problems... Hell, I wouldn't doubt this hack alone hasn't generated some increased tech-support for some vendors)