Question: do you need two of the same graphics card for sli?
Answer: In SLI, you need two cards that have the same GPU—for example, two GTX 560 Tis. They don't have to be from the same manufacturer, they just have to both be GTX 560 Tis. ... To see which cards are compatible with one another, check out NVIDIA's SLI page and AMD's Crossfire page.