Ive used the 6600GT in single and dual SLi mode, and those things scream! Basically, OCed, Money_Man is getting huge scores on 3DMARK03 and 05' with relative ease, and the eVGA and MSI 6600GTs with OpenGL 2.0 support are EXTREMELY good, VERY FAST, well built and cooled (MSI has better cooling), and VERY CHEAP (under $190)