No, on your K7S5A, you have a Sempron 2100+ or so. In order to reach the 2500+ rating (1750mhz), you need to run at the full 333mhz FSB. At 266mhz FSB, you only get 1400mhz, which is exactly what an Athlon XP 1600+ is.
If 1750 is a Sempron 2500
1667 is Sempron 2400
1584 is Sempron 2300
1500 is Sempron 2200
1418 is Sempron 2100. But that assumes a 333mhz FSB still.