Apple released the Nvidia Graphics Update 2009 which deals with video smoothness issues on Macs equipped with GeForce 7300 GT or GeForce 9600M graphics cards, and also improves HD video playback on affected models. The primary fix involves cursor movement and visibility when a Mac (MacBoook, MacBook Pro, MacBook Air) with one of these Nvidia cards is using a Dual-link DVI adaptor connected to the Mini DisplayPort. This particular piece of hardware was a requirement for anyone who bought an updated Mac in October and wanted to use it with a 30” external monitor. Unfortunately, the $99 product wasn't available until the end of December.

Source:→ BetaNews