Only the 6950/6970/6990 have the arch differences. The 68xx are exactly like the 58xx series except with less shaders
Right on. The 6800's are more like the 5800's than the 6900's. In any event, I don't think the much older 5000 series is going to benefit from any driver updates. In fact, after reading the recent Tom's article, I don't think the 6000 series is going to get much of one either.