The only reason the GT and new GTS are significantly faster over the old GTS is because they have had major changes, the texture units etc... have been increased, the 3870's though are still the same 320 streams, 16 rops etc... exact same as 2900.
yep, you are correct thats why the performance of the 3870 is around the same as a 2900, and thats not saying much seeing how a 2900 is slower than a 8800gt, slap on the AA and the 2900 is slower than an old skool gts 640.
the onlything fishy is the transistor count, 2900 got 700, 3870 has 666, im guessing the reduction could be due to the smaller memory interface and ringbus controller complexity.
either way the 3870 doesn;t have the architectural advantages over the 2900 like the new g92 gt/gts have over the g80 8800gts/gtx.
not sure why these guys don;t understand what your saying loadsamoney, what your saying makes perfect sense, you probably have to dumb it down for the fanboys.