As far as I can see, the newest drivers are delivering quite a bit of a performance improvement over the previous drivers.
NVIDIA released its latest version of the GeForce driver suite, version 197.55, specific to the GeForce GTX 400 series graphics cards. The WHQL-signed drivers don't announce any more changes than a major feature change - official support for 4-way SLI on both GeForce GTX 480 and GeForce GTX 470. The drivers only work with GeForce 400 series products. No Release Notes documents were published along with the drivers. (DOWNLOAD 32-bit, DOWNLOAD 64-bit)