Help with Sli please

[STSquirtle]

Alright guys i have a headache inducing problem right now going on when i try to sli my two gtx 660 ti cards together.

My hardware list include these:

1 MSI N660ti TF (twin frozr) 3GB OC edition gpu

1 Nvdia 660ti reference card. (from geforce gtx. The one you buy at best buy)

Power supply is a Cooler Master 1250w Real power Pro

Motherboard is a Gigabyte GA-990FXA-UD7 with an 8150 AMD cpu. (has f10 bios installed)

Alright so my big problem is that i can't get the sli option to pop up on my nvdia control panel where it should be with physx. I have tried to move my cards into 4 different PCIE slots from 16x to 8x bandwidths. I have tried one hard and one soft sli bridge. I have tried to re-flash my bios and re-install my nvdia drivers and to no avail have i had any luck what so ever.

So at this moment i am out of stuff that i can think of. And my MSI 660 is now acting as a dedicated physx processor :p. Do you guys have any suggestions that maybe able to help with my problem. Thanks for reading this guys

[Raider102002]

Try to clock them the same

That might help i hope

[mralexkohl1993]

you cant do 2 cards that have different PCB designs. the 3 gig card will not work with the 2 gig and vise versa because they are technically different cards.

[Caesar Rex]

you cant do 2 cards that have different PCB designs. the 3 gig card will not work with the 2 gig and vise versa because they are technically different cards.

This is also my guess.

[Brendan]

3gb does not work with 2gb

[STSquirtle]

Well that was a stupid mistake lol. Thanks for the replies