Nvidia said that the new driver will increase the performance for the 400/500/600 GPU Series in "several PC games" when compared to the 301.42 driver. The release notes of the driver lists improvements for:
GeForce GTX 680:
Up to 18% in Batman: Arkham City
Up to 15% in Dragon Age II
Up to 10% in S.T.A.L.K.E.R.: Call of Pripyat
Up to 60% in Total War: Shogun 2 (fixes performance issue with latest game patch)
GeForce GTX 560:
Up to 14% in Batman: Arkham City
Up to 5% in Battlefield 3 with SLI
Up to 4% in Dragon Age II
Up to 8% in The Witcher 2: Assassins of Kings with SLI
Up to 7% in Lost Planet 2
Additionally, the driver updates numerous SLI game profiles, adds and updates 3D Vision profiles to games, fixes a surround sound issue after a new driver install, supports applications using CUDA 5, solves an intermittent vsync stuttering issue with GeForce GTX 600-series GPUs, as well as a problem "where some manufacturer's factory overclocked cards default to and run at lower clocks."
Also added are support for OpenGL 4.3 for GeForce 400-series and later GPUs, and DisplayPort 1.2 for GeForce GTX 600 series GPUs. Details of the new driver can be found in the release notes of the driver.