Here's what you can expect on the performance side of things, according to Nvidia:
Up to 10% performance increase in 3DMark Vantage (performance preset)
Up to 13% performance increase in Assassin's Creed
Up to 13% performance increase in BioShock
Up to 15% performance increase in Company of Heroes: Opposing Fronts
Up to 10% performance increase in Crysis Warhead
Up to 25% performance increase in Devil May Cry 4
Up to 38% performance increase in Far Cry 2
Up to 18% performance increase in Race Driver: GRID
Up to 80% performance increase in Lost Planet: Colonies
Up to 18% performance increase in World of Conflict
There are some caveats, however. For one, the 180.48 release only supports GeForce 200-series, GeForce 9, and GeForce 8800-series graphics cards. Also, SLI multi-display support apparently doesn't work in Windows XP for now. Finally, Nvidia says X58 mobos will only work in SLI mode with GeForce 9800 GTX, 9800 GTX+, 9800 GX2, and 200-series GPUs.