I can't very well talk about old CPU's and not mention the 6809. One of the best 8-bit CPUs created, some even say it was the best. It was used in the Tandy Color Computer's. The Motorola 6809E ran at 0.895 MHz or 1.79 MHz. BASIC would run the machine at 0.895 MHz but with a poke, you could put the speed at 1.79. Boy that was fast!
Couple links:
Instruction set I'm working on
https://en.wikipedia.org/wiki/Instructions_per_second
Really getting a number of good links setup http://ogsteviestrow.com/coco/
Dungeons of Daggorath, for Mac, for PC
| Processor / System | Dhrystone MIPS / MIPS | D IPS / clock cycles per second | Year |
| Intel 8080 | 0.29 MIPS at 2 MHz | 0.145 | 1974 |
| Zilog Z80 | 0.58 MIPS at 4 MHz | 0.145 | 1976 |
| Motorola 6809 | 0.42 MIPS at 1 MHz | 0.42 | 1977 |
| Intel 8086 | 0.33 MIPS at 5 MHz | 0.066 | 1978 |
| Intel 8088 | 0.75 MIPS at 10 MHz | 0.075 | 1979 |
| Motorola 68000 | 1.4 MIPS at 8 MHz | 0.175 | 1979 |
| Intel 286 | 1.28 MIPS at 12 MHz | 0.107 | 1982 |
| Intel i386DX | 2.15 MIPS at 16 MHz | 0.134 | 1985 |
| Intel i386DX | 4.3 MIPS at 33 MHz | 0.13 | 1989 |
| Intel i486DX | 8.7 MIPS at 25 MHz | 0.348 | 1989 |
| Intel i486DX | 11.1 MIPS at 33 MHz | 0.336 | 1991 |