Athlon XP2000+ upgrade on unknown board

[SteveC]

I have read the various posts and tried to identify my mother board so i can find a better CPU, but no brand is shown when CPU-Z is used. The following is available:
Motherboard: KM400-8235 (0x0000022B - 0x17198A88)
Socket A (462)
Core speed: 1667.0 MHz
Northbridge VIA KM400 rev. 00
Southbridge VIA VT8235 rev. 00
Memory Frequency 166.7 MHz (FSB + 33 MHz)
FSB speed 133.0 MHz
multiplier 12.5x
Any ideas which CPUs could improve performance on this old machine? All advice welcome

[Neon_WA]