Easily Switch Between Your MacBook Pro's Graphics Cards with gfxCardStatus
A new application called gfxCardStatus will allow you to discretely switch between the on-board and NVIDIA graphics cards in your MacBook Pro. Unfortunately, this application only works with MBPs that have the NVIDIA GeForce GT 330M graphics cards.This simple application sits in your menubar until you need to switch graphics cards. Normally, you would have to log out to do this, but now you just need to click the application in the menu bar and select "Switch GPUs". After a short while, your graphics cards will be switched and you can go about your business.There's a little room for improvement, but this application is neat none-the-less. The application, created by Cody Krieger, is available for free from his website.via Engadget
http://www.maclife.com/article/news/easily_switch_between_your_macbook_pros_graphics_cards_gfxcardstatus
