AMD made a late announcement on Thursday expanding its Radeon for Mac lineup. The ATI-branded Radeon HD 3870 for Mac & PC is AMD's first 3000-series card for Macs and also one of the first to explicitly support more than one platform: users can install the card now in either a Mac Pro tower or a Windows PC and swap it to the other platform later, including for Boot Camp. As a new-generation part, the new chipset has twice as much performance per watt as the outgoing Radeon HD 2900 XT, the company claims.

AMD's card is virtually equal to the Windows-only edition with 320 stream (pixel and vertex) processors, improved power use, and support for newer graphics shader effects either in DirectX 10.1 when in Windows or OpenGL 2.0 in OS X and other environments.

For connections, the new Radeon HD board is built to outpace Apple's own offerings with both dual-link DVI ports that handle 30-inch displays as well as an S-video jack for analog video from TVs. AMD is shipping the card by the end of June in a 512MB version for $219 and expects it to be available at a number of Mac resellers.