Phoronix reports that AMD is in the process of pushing new high-end features into their Linux driver such as Multi-GPU CrossFire support

"Less than a year ago we shared with you the revolutionary steps AMD was taking to deliver significant improvements to their once infamous proprietary Linux display driver and at the same time the work they were doing to foster the growth of an open-source driver for their latest graphics card families. These steps have certainly paid off for both AMD and the Linux community at large. AMD's proprietary driver is now on par with NVIDIA's Linux driver and there are two open-source ATI drivers picking up new features and improvements on an almost daily basis. AMD also continues to publish new programming guides and register information on a routine basis for their latest and greatest hardware. This has been truly phenomenal to see, but AMD has now evolved their Linux support by taking it a large step further. AMD is in the process of pushing new high-end features into their Linux driver -- such as Multi-GPU CrossFire support -- and with the ATI Radeon HD 4850 they have even begun showing off Tux, the Linux mascot, on their product packaging and providing Linux drivers on their product CDs!"

>> AMD Makes An Evolutionary Leap In Linux Support