I finally got SLI working on my X48 Mobo. So, by posting here, maybe someone else searching will be helped.
Gigabyte GA-X48-DQ6 Mobo (775 Socket)
Gigabyte (2) GT 560Ti Graphics Cards
Windows 7 Ultimate 64bit
Nvidia Drivers 266.66
AntiVirus: Avast Free (This Plays a part in it)
External Graphics: Matrox TH2GO Digital Edition
Okay, I downloaded SLI Patch .9B from the guys over at Xdevs
. Installed. Got a warning from Avast about a rootkit right after installing the .9B, so I selected delete it. Restarted my machine, selected SLI mode, got the Windows Logo then BAM, Blue Screen of Death (BSOD), Crash dump, reboot.
So, selected normal windows startup. Downloaded Driver Sweeper, uninstalled SLI patch, Uninstalled Drivers, Drive sweeper Nvidia Drivers, turned off my PC. Uninstalled second Vid Card from Mobo, just left one in. Powered up PC, booted into Windows normally.
Installed 266.66 drivers, reboot, install SLI Patch 1.42 found on page 1 of this thread, reboot, upon reboot I selected SLI boot mode, got to Windows Logo and BAM, BSOD, Crash Dump, reboot.
Ok, I remembered that error warning from Avast, soooooo... I booted normally (no sli), uninstalled SLI Patch 1.42, uninstalled Nvidia Drivers, Ran Drive Sweeper to clear them out, I uninstalled Avast and I uninstalled Matrox GXM software just to be sure. Rebooted.
Started up windows normally, installed Nvidia Drivers, reboot. After Reboot, I installed SLI Patch 1.42 Beta, rebooted. I then selected SLI mode and....No BAM, No BSOD, Booted just fine. Oooooh could it be...
I then shut down my PC, installed my second Vid Card, I had to use an Asus SLI connector that's been sitting in my parts bin for a few years (Asus brand, ironic isn't it, given SLI Patch uses Asus to fake out SLI).
Booted up the PC, Windows Loaded just fine. Went to Nvidia Control Panel, there it was, SLI. Selected it, hit apply, and......it worked. Turned on SLI indicators, entered a game and there was the SLI in its full glory.
I then re-installed my Matrox GXM software, rebooted, windows came up, no issues. I re-installed Avast, rebooted, windows came up, no issues.
Did a virus scan, nothing found. I think Avast didn't like what the SLI patch was doing, once it detected it, and I said delete it, it prevented the SLI patch from completing from that point on, no matter how many re-installs I did.
Only by uninstalling Avast and starting over did it work. I was thinking about updating to 270 drivers, but, I've been reading some issues with Graphic Artifacts, issues with SLI, and not sure if 1.42 will work with it. So, I'm sticking with 266 until...well...until I'm forced to change.
Happy SLI'ing out there.