| CPU Type | Year Relased | Clock Speed | Front-side bus | |
| Intel | 8088 | 1978 | 4.77 MHZ | N/A same |
| 8086 | 1978 | 5, 8, and 10 MHZ | N/A same | |
| 286 | 1982 | 8, 10, and 12 MHZ | N/A same | |
| 386 | 1985 | 16 to 40mhz | N/A, 8MHZ for some IO | |
| 486 | 1989 | 16 to 100 MHZ | ?? not faster then 40MHZ | |
| Pentium | 1993 | 60 to 233 MHZ | 60 or 66 MHZ | |
| Pentium Pro | 1995 | 150, 166, 180, 200, and 233 MHZ | 60 or 66 MHZ | |
| Pentium 2 | 1997 | 233 to 533 MHZ | 66 or 100 MHZ | |
| Pentium 3 | 1999 | 450 MHZ upto 1.3GHZ | 100 or 133 MHZ | |
| Pentium 4 | 2000 | 1.3GHZ upto 3.3GHZ | 533 and 877 MHZ | |