Solution
the most you can do is physx card one of them. to sli nvidia cards, you need 2 exact gpu models(doesnt have to be same company just main model) the faster card then will downlock itself to whatever the slower card is.
the most you can do is physx card one of them. to sli nvidia cards, you need 2 exact gpu models(doesnt have to be same company just main model) the faster card then will downlock itself to whatever the slower card is.
 
Solution