1.79 MHz 6502/65C02 x 4 (half a colour clock)
4 MHz Z80 x 2 (and another in my TI-83 calc)
8/16 MHz 68000
16 MHz 80386sx (long gone, due to motherboard failure)
25/50 MHz 68040 which replaced a 68LC040
225 MHz PPC604e which replaced a 120 MHz PPC604
233 MHz PPC750 (long gone, due to pathetic performance)
800 MHz PPC750fx which replaced a 400 MHz PPC750
800 MHz PPC744x x 2
1.33 GHz PPC7447