I run a Toshiba Pentium III (Win98SE), and I would venture to guess it is around 500 Mhz. I have never had any problems with Motorola or Kenwood software on this machine. I have to slow it down when running Standard PPS software, and I can do that in the BIOS. Never have had to run MOSLO.
As far as with working with AMD, that I do not know, never had too many boxes with AMD processors.