Hello,
I have an asus gtx 550 ti, do i have to use another asus gtx 550 ti or can i use another brand like galaxy gtx 550 ti for both cards to work in sli mode.
But you still have to make sure that the cards have the same Core, Memory Clocks or you'll have to OC the lowest card.
otherwise the faster card will down clock to the slower card. You essentially would be buying (if you do not oc your current card) performance that wont be used.