Apple has released an update for MacBook, MacBooks Air, and MacBook Pro with Mini DisplayPort called, "Nvidia Graphics Update 2009 1.0." The update improves cursor performance and playback of HD video with certain graphics chipsets.
The release notes in full from Apple: "This update improves cursor movement when using the Apple Mini DisplayPort to Dual-Link DVI adapter with the Mini DisplayPort enabled MacBook Air, MacBook and MacBook Pro. It also improves playback of HD video running on systems with Nvidia GeForce 7300 GT or GeForce 9600M graphics."
The update is a 3.1 MB download, and it can be accessed through Software Update.