SLI wont work when both cards dont match

[pureprojection]

You can edit one card bios change subsys ID and board Id no. then copy it to the other card bios. SLI well then work. I only used two 6800 GS PCI-E cards one was PNY other PNY after market I could not get the SLI to Engage even when software says it is. Bench mark shows it was not. I bet you could use any card of same basic specs use edit program make one board look like other board?

 

[ktr]

Do you have the sli enabled in the nvidia control panel? If it is, enable sli indicator and play a game, only then you will see if your sli is working.