Intel Pentium III

The raw FPU performance of the Pentium III is not improved at all in comparison to the Pentium II 450, the increase in clock speed is the only difference here. 

Here you can begin to see the potential SSE has for the Pentium III.  Just as 3DNow! did for the K6-2, SSE brings the Pentium III to new levels of performance.  Rage's Dispatch demo, a 3965 frame fly through demo of actual gameplay of the upcoming game, Dispatch, truly taxed even AnandTech's fastest Pentium II systems.  The Pentium III 560 only scored just under 26 fps, however after turning on the SSE support that was built in to the game, the performance of the Pentium III almost doubled offering a 96% performance improvement.  Although the performance improvement experienced in Dispatch can be considered the ideal case, you can expect performance improvements to hover around the 20 - 40% range just by enabling SSE in future games.   The potential is there, the weight is placed on the shoulders of game developers and video card manufacturers to take advantage of Intel's new born baby.