I am looking at getting some new graphics cards for my computer, either 2 AMD 6990's in Crossfire, or 2 NVIDIA Geforce GTX 590's in SLI...I'm just wondering which one is better performance wise, and what the best brand is for both the 6990's and the 590's (e.g. EVGA, Powercolor, XFX etc)
Stay away from AMD cards right now. Also stay away from the 590. Get yourself a 580 SLI, and if your motherboard can't support 2 cards in SLI, just make do with one 580. Honestly, it's what I would do.