what's the differences between 8600 gts and 8600 gt?

Question

are gts really powerful than gt or it just few frames per second

are it will left far the gt in benchmark

Answer 1

Main difference is the clock speed (core and memory).
http://anandtech.com/video/showdoc.aspx?i=2970&p=2
Some benchmarks here:
http://anandtech.com/video/showdoc.aspx?i=2970&p=6
http://anandtech.com/video/showdoc.aspx?i=2970&p=7

Answer 2

8600 gts in better from 8600 gt as it contains large number of pipe lines and contain faster memory clock speed. But if u want good performance in good price 8600GT is the one for u.