Question: I have plug two NVIDIA® VGA cards on my motherboard but, I cannot find the Enable SLI option in NVIDIA® Control panel?(9/3/2009) Answer: Following steps as below may help you to solve this issue.
1. If your motherboard has the SLI/XFire switch card, please put the SLI/XFire Switch card to 8x/8x, if there is no switch card on your motherboard, please skip this step.
2. Remove the graphics card from the PCI-E 1 slot.
3. Restart Windows.
4. Install the driver for the graphics card (again).
5. Put the VGA card back into the PCI-E 1 slot, and put the SLI bridge on.
6. Activate SLI function by NVIDIA® control panel.