Well, there are plenty of factors that affect gaming performance.
1. windows XP - certainly slower than win98, maybe the performance hit is bigger for AMD and lower for Intel
2. fast VGA - GF 6800 Ultra is overkill for testing this level of CPU performance. Some CPUs may profit more from it, and others less. What videocard are you using?
3. Motherboard, especially VIA based boards are hit and miss. Some of them are rather fast, others are terrible.
That KT133A I used is rather good, imho. KT266A Biostar on the other hand.... not so much. But it is the only period-correct DDR-based s462 MB I have. Still better than AMD-760MPX, but far from perfect, thats for sure. Asus TUSL2 is one of the best s370 boards and Tualatin performance proves it.
PIII-S is good, no doubt. Athlon XP may be better when running on fast chipset and MB... look at Q3A performance:
Athlon 1400 (KT133A) =136,1
Athlon 1400 (KT266A) = 144,4
Athlon XP 1600+ (KT266A) = 134,6
Athlon XP 2000+ (nForce2 U400) = 182,3
PIII-S 1400 = 148
Raw FPU performance is not the only important thing. Memory and cache performance matters a lot and VIA chipsets are usually much slower than Intel. Just as AMD cache is almost always slower and higher latency.
HW museum.cz - my collection of PC hardware