SLI bombing out

[DefDC]

Hardware:
Mobo: ASUS M4N72-E
RAM: 4GB Crucial DDR2
Proc: AMD Phenom II 940c Black
Video Card1: BFG 9800GT
Video Card2: XFX 9800GT
OS: Win7 64bit
PSU: 500W Thermaltake


I decided to give SLI a shot before spending the cash on a new card.

The first card (BFG) installed without a problem. I had been using this card in another computer for a while. Gaming was fine. No issues. I installed the 2nd card, and it installed without a problem. Both looking fine in the Hardware Manager. I had hooked up the SLI connector before booting.

Windows loaded and said was SLI capable, so I go to to the nVidia control panel. I enable for "Best 3D performance" and it starting "Applying Settings". The video flashes, it disables both cards, and now I'm stuck with the default windows video driver. And I no longer get the option to go to the nVidia control panel. If I go through the "Start Menu" and click on the nVidia control panel, it does nothing. If I right click on the desktop, it's gone.

So far I've:
Used the most current drivers from nVidia
Updated the mobo BIOS (and drivers)
Tried using the SLI connector (and not)
Removed all video drivers, and reinstalled them fresh with the same results.

The cards both work fine individually... While researching, I've seen some (very few) people mentioning similar problems,and their resolution was usually a BIOS upgrade. (Different hardware and OS than mine every time)

I can the get the video back by reinstalling the drivers, or removing the cards from the Hardware manager and rebooting. But as soon as I attempt to SLI again, it bombs out.

My main video card in this rig was an MSI 8800GT, but I pulled that card and replaced it with the BFG 9800GT.

I'm running out of ideas. This is my 1st time attempting SLI. I'm not missing anything, am I?

 

[Keysplayr]

Do the cards have the same amount of memory? 512 or 1GB versions?
If so, then try this:

Download the latest mobo chipset drivers for your board from ASUS for your OS.
Download the latest Nvidia drivers for your cards and OS.
Update all mobo drivers. Reboot if it asks you to.
Uninstall Nvidia Display driver ONLY in the Add remove programs in Control Panel.
Shut down.
Remove both cards and place the 2nd card you are adding into the primary PCI-e slot and hook up the PCI-e power cable(s).
Leave the second card out for now.
Boot up and cancel any "Hardware Device Found" messages that pop up.
Install the latest Nvidia display driver.
Reboot. After OS is loaded, check to see that you have the "Nvidia Control Panel" option when you right click on the desktop.
If it's all good, shut down and add the second card. No SLI bridge yet.
Boot up and see if the new Nvidia driver installs on it's own for the second card.
If it does and it checks out in Device Manager, shut down and put on the SLI bridge.
Boot up.
Enable SLI in the control panel when the balloon popup appears.

Let me know how you make out.

Keys

 

[DefDC]

That's pretty much what I did, but at least that confirms I didn't do anything wrong or miss a step.

These are both 512MB cards. At least I *THINK* the XFX card is 512. I'll double check when I get home from work. If the XFX is 1gb, would you make it the primary? Does it matter since it'll only use 512 anyways?

Is there any reason to pick one card over another for PhysX?

Once I get home, I'll pull everything, start from scratch, and go one step at a time.