The entire 8 series is built on the same architecture. IN fact the difference between some of the cards is actually which came out of the factory with more working parts, and which didn't meet the qualifications for the highest end due to a bad fab,in which case they disable to bring it in spec with the lower card. Kinda funny, but good strategy in terms of reusing what would otherwise be dud componets. Apparently NVidia has been doing this since the 6 series...
http://arstechnica.com/articles/paed...and-beyond.ars
Great article that just got posted a few hours ago explaining it.
At any rate, the mid-range cards (8500 and 8600) have a smaller number of stream processors, but they certainly still have them. And they could conceivably still be taken advantage of, is someone wrote the code to do it. I may eventually look at doing it for Ardour/Jack/LAU, but that would be a big IF as I am just now trying to brush up my C to a decent level and might not have time, especially if I get the job I am aiming for.
Seablade