TrustedReviews have looked at the BFG GeForce 8800 GTS

In this case, going from the GTX to a GTS means a price reduction of close to £150. By moving from the GTX to the GTS, we see a drop in the number of stream processors from 128 to 96. These are also running at a slower frequency of 1.2GHz, compared to the 1.35GHz of the GTX. We also
see a drop in the number of pixel output engines, from 24 to 20. This drop in pixel throughput should only really be an issue at very high resolutions.

BFG GeForce 8800 GTS Review