perkam that's highly unlikely and you know that. The worst scenario we've seen for the 4870 is gddr5 memory with 480 shaders and more TMUs. I'd be willing to bet the 480 shaders is correct because that would support the rumors about the 4470 and 4670 with 120 and 240 shaders (meaning clusters of 120). TMU number is beyond me though if we're going to clusters of 120, but it's definitely going to be higher, and there's a lot of talk of 3:1 Alu:TMU with 96:32.

So worst come worst, we'll see at least a 50% gain due to the 50% more shaders and higher clocks, meaning at least a good 10% over the 9800gtx. And that's not accounting for how performance will be without the huge TMU bottleneck and plenty of shaders for AA