The new core (R250) is just that, a new GPU. What performance gains it will bring are unknown, but it seems obvious that it *at least* clocks about 30% faster.
You are right about the memory speed being more important that clock speed, but that was with the old R200 core. I guess we'll have to wait and see what the benchmarks show, and then look at the price/performance. At the very least, the price of the 8500 should drop.
I guess the rumors of the 8700 being 300/300 and the 8800 being 350/350 werent quite true, if that link is correct.
Oh well, guess that means Ill have to wait a little while longer to upgrage my card.