Wow, almost embarassing to post:) Oh well, my dual 1ghz P3 system will be built soon, and it'll do better.
This is my P3 667mhz
[Jun 02 04:40:26 UTC] Benchmark for RC5 core #2 (RG class 6)
0.00:00:08.46 [1,858,971.75 keys/sec]
My Pentium 200 MMX did 417k keys/s