I'm no expert but I do know what a single gtx 450 runs wow at "about" 40 fps on ultra for 1 single char not in window mode. I've read with SLI crossfire you don't gain 100% perks from adding an additional card. The 2 cards you already have will most likely out perform 3 lesser cards. You may want to upgrade to the gtx 700 series. A single 770 or 780 should suit your needs just fine for only doing a 2 box. But you will be looking at a little bit of price. You may get lucky if you search around and scoop either card for around 300 bucks. If you can manage to run 2, you'll be better off for future protection.


I'm no expert though, I'm just someone that reads a lot and truthfully I haven't ever multi boxed but based off what I know about tech stuff. Minus the stuff I heard today about 27 gb of RAM being used for WoW. That totally blew me away. I'm pretty savy when it comes to setting something up that will run games. Even if you can get a few 660 2gbs to run in SLI you should have no problems. 1 would probably do it, but 2 would give the extra comfort of knowing that your graphics can handle what you're giving it. The 700 series cards would just add the benefit of knowing you won't have to upgrade for a while.