GeForce Forceware 266.58 Windows XP | 7 | Vista are out for grabs.

Performance

Increases performance for GeForce 400 Series and 500 Series GPUs in several PC games vs. the latest Release 260 drivers. The following are examples of some of the most significant improvements measured on Windows 7. Results will vary depending on your GPU and system configuration:

GeForce GTX 580:

o Up to 7% in Battlefield Bad Company 2 (1920x1200 4xAA/16xAF)
o Up to 12% in Battleforge (SLI 1920x1200 4xAA/16xAF Very High)
o Up to 11% in Call of Duty: Modern Warfare 2 (SLI 1920x1200 4xAA/16xAF)
o Up to 7% in Dirt 2 (SLI 1920x1200 4xAA/16xAF)
o Up to 7% in Far Cry 2 (1920x1200 4xAA/16xAF)
o Up to 5% in Just Cause 2 (1920x1200 4xAA/16xAF Dark Tower)
o Up to 5% in S.T.A.L.K.E.R.: Call of Pripyat (SLI