UB
I think you've made an error in your maths somewhere. The Athlon/Duron series is about 20 faster per Mhz than a P3.
Taking your figures.
P3
2,684,275.04 KEYS/SEC = 2877 KEYS per MHZ per SECOND
MP
5,172,332.39/1400 = 3694 KEYS per MHZ per SECOND
The athlon is 28% faster than the P3
Russman