Yesterday’s release of Mac OS X 10.5.7 included a pleasant surprise among the flurry of updates for the Mac operating system—integrated support for ATI’s Radeon HD 4870 card.

The Radeon HD 4870 has been a configure-to-order option for new Mac Pro buyers since the line had been updated this past March. At the same time, Apple introduced a Radeon HD 4870 kit for Mac Pro users who had purchased the system in 2008, which would upgrade the older Nvidia card to the faster Radeon. The GPU promises a significant speed improvement over other graphics processors offered with the Mac Pro, along with additional support for the Mini DisplayPort interface found on Apple’s 24-inch Cinema LED Display.

Currently, the Mac Pro comes with the option of an Nvidia Geforce GT 120 with 512MB of memory or the Radeon HD 4870. Early 2008 Mac Pro models shipped with either an ATI Radeon 2600XT or Nvidia 8800Gt, both of which are significantly slower than the Radeon 4870.

The 10.5.7 update includes support for extensions to OpenGL, Apple’s 3D graphics Application Programming Interface (API) required to support the Radeon HD 4870. You can download the update here.