so your brother likes to play WoW and LoL, eh? sorry, i couldn't help it...it just looks/sounds funny.
for starters, the 890FX is an AMD chipset that's Crossfire capable, not SLI capable. so you might want to consider getting a top-of-the-line (or at least high-end) AMD/ATI "Crossfire-ready" video card instead of the "SLI-ready" nVidia video card you have picked out. even if the nearest equivalent AMD card is less of a performer, at least your bro will have the option of adding another AMD video card down the road to make for a Crossfire combination that will surely outperform a single nVidia 570 GTX. heck, he might even be able to outperform a single 570 GTX if he simply starts out with a pair of the right 5xxx or 4xxx seires AMD video cards. note that this is not to say that an nVidia video card will not work on a mobo w/ an AMD chipset (and likewise, an AMD/ATI video card should work on a mobo w/ an nVidia chipset). but you won't be able to run two or more nVidia video cards in SLI mode on a mobo that has Crossfire support, and vice versa.
i'm sure as heck no video card expert (especially since i've stopped playing PC games for the most part several years ago), but the fact that you have an nVidia card paired with a Crossfire capable mobo is the first thing that stood out to me...perhaps some of the video card gurus and gamers on the boards could confirm the above, as i'm looking to use the Crossfire feature on my M4A89GTD PRO/USB3 mobo in the near future, and would hate to make any mistakes in choosing the right video card(s).
