Hello, I have tried everything to try and get these two cards to work. From driver updates, to updating the bios on my mb. I had sli working before with 2 460's but one card died and I rma'd it. The new card is the same, but overclocked. And apantly, from my check they are both version2 cards.
my specs: windows 7 64i7 3930k 16GB RAM X79 Sabertooth Asus MB palit gtx 460 2048MB palit gtx 460 1024MB
Make sure they are the same clock and you have the power suppyl for it.
One has different memory. You need coolbits software to make it work.