Why should 4870 be only %50 (and even that "with a lot of wishful thinking") faster than 3870 when its processing power doubled, memory bandwidth doubled, memory amount doubled, texture addressing/filtering more than doubled, and z-fillrate at least doubled?

And if 4870 is %50 better than 3870, which makes 4850 only %10 or 15 better than 3870; how the hell can AMD/ATi justify 4850's price of $220, whereas HD3870's are as low as $150?

I would expect 4870 to be close to twice 3870, which would justify both part's prices and specifications.