FWIW..
I have a KT3 Ultra2 with a xp2100+ Tbred"b" and 333ddr (cas2.5).
I did the "wire trick" in the cpu socket (single wire), which let me pick any multiplier.. but only in the low range (4.5 to 13). Since 133x13 didnt get me any faster than stock, I pushed the fsb up to 166 (and backed the mem down to SPD (166).
So now its 166x13 ( 2100 Mhz.) and posts as a xp2600+. CPUID et al report this also. The agp and pci dividers must autmatically step down ?
The Volcano7 cooler runs faster now, and I had to do some case mods to get the temp down, currently idles at 113F (cpu) and will run up to 120/125 in intense gaming.
If you guys want a giggle.. my "case" mod was this:
Put a 80mm fan into the vent hole at rear, so now all fans (psu and a slot cooler, plus this new fan) all blow outward. Then I cut a 4x10" hole in my side panel, between the drive bays and the floor. Put a 4x10" heating floor register (home heating part) in there and a filter element made for these. From the outside I think it looks a little cool.. and it works slick, and no more dust bunnies.
Cheers.