Why? Well first off, its performance is stellar. It manages to be approximately 50% better than the 3870, 9800GTX, etc. It's on par with the 9800GX2. The 4850 25% slower than the 4870, which is 10% slower than the 280GTX, which makes the 4850 ~35% slower than the 280GTX.

This is significant why? While the 4850 is 35% slower than a 280GTX, it costs $450 less. 33% the price, 65% of the performance. It also draws almost 1/3 the power and thus puts out ~1/3 the heat. It's as fast...