Intel Celeron 600 "Coppermine128"

Going from a 66MHz FSB and 66MHz memory bus up to 100/100MHz results in a 38% improvement in performance under Quake III with 17% of that due to the increase in the memory bus and the remaining 21% due to the increase in FSB frequency.

While the performance difference isn't as dramatic at the higher resolution it is still fairly noticeable at 31%. With just about half of that increase being due to the increase in memory bus frequency, the other half being attributed to the increased FSB frequency.