I am guessing that the HD 4890 will be available for Macs sometime late Summer or early Fall. My reasoning: The Mac HD 3870 became available in April of 2008. The PC HD 4870 was released a month later. The Mac HD 4870 became available in March of 2009. The PC HD 4890 was released a month later. Rumor has the HD 5870 may be released for PCs sometime late Summer or early Fall. Going by previous history, the HD 4890 for Macs should be available one month before the HD 5870 release Or with a little luck, maybe the HD 4890 driver will be included in the release of Snow Leopard. By the way, contrary to previous rumors, ATI is now expected to launch the HD 4890 X2. ATI’s hand was forced when NVIDIA came out with the GTX 295. Drool Time: The HD 5870 is expected to have 50 percent more shaders than the HD 4870. It will have a 40nm die fabrication which means improved clock speeds, much lower heat, and much improved performance, especially if they use that extra space to increase the shader processors to 1200 or more as well as increasing the ROP's and putting in a 512-bit bus to take full advantage of that GDDR5. Thanks in part to the small size of the GPU, the HD 5870 X2 is going not have two separate GPU's, instead it will be two RV770 cores stacked on top of each other. That also means the gpu will be small enough to stack four RV770s on top of each other to make a single video card called the HD 5870 X4. Radeon HD 5870 ------ 512MB, 1200 sp, dual MCM, 800MHz Core, 1200MHz GDDR5 Radeon HD 5870 X2 - 2GB, 1200 x2 sp, dual MCM, 800MHz Core, 1200MHz GDDR5 Radeon HD 5870 X4 - 4GB, 1200 x4 sp, dual MCM, 800MHz Core, 1200MHz GDDR5 NVIDIA is expected to bring out a new card; the NV GTX 390 - 3.6GB, 1792 bit memory connection, 4 gpus on one card.