Graphics drivers on OSX don't come from Apple. They're written by ATI/Nvidia. However, for a variety of reasons including larger development teams and end user

Graphics drivers on OSX don't come from Apple. They're written by ATI/Nvidia. However, for a variety of reasons including larger development teams and end user upgradeability, Windows drivers just have the cutting edge tech available first. Just like with Apple, were you to go to Dell.com or HP.com and download manufacturer certified drivers, you'd find them woefully out of date also.