Both AMD and Nvidia, in addition to selling reference cards directly, also allow their partners (authorized video card suppliers ) to sell their graphics cards. These are for example EVGA and Zotac( Nvidia partners ), XFX and Sapphire ( AMD partners ). Do you pay any attention to these brands when you're buying graphics cards ? I don't. I just buy the cheapest model of a particular card to save money, since they seem to work just as well as more expensive models from other brands like ASUS Strix.