saumilsingh said:sm3 isn't a gimmick, it actually runs older shader effects faster than sm2b (far cry is faster in sm3 mode if you don't turn on hdr) and allows for a few newer effects of its own (that's where it slows down on mid-range cards like the 6600gt).
Albeit framerates in the 30's is very normal and might I say good for splinter cell games at 1280x1024, I didn't see the last 2 perform any better unless I dropped to a lowly 1024x768.