CPU Evolution

Chronological Evolution of CPUs

Type/ Generation	Year	Data/ Address bus width	Level 1 Cache (KB)	Memory bus speed (MHz)	Internal clock speed (MHz)
8088/ First	1979	8/20 bit	None	4.77-8	4.77-8
8086/ First	1978	16/20 bit	None	4.77-8	4.77-8
80286/ Second	1982	16/24 bit	None	6-20	6-20
80386DX/ Third	1985	32/32 bit	None	16-33	16-33
80386SX/ Third	1988	16/32 bit	8	16-33	16-33
80486DX/ Fourth	1989	32/32 bit	8	25-50	25-50
80486SX/ Fourth	1989	32/32 bit	8	25-50	25-50
80486DX2/ Fourth	1992	32/32 bit	8	25-40	50-80
80486DX4/ Fourth	1994	32/32 bit	8+8	25-40	75-120
Pentium/ Fifth	1993	64/32 bit	8+8	60-66	60-200
MMX/ Fifth	1997	64/32 bit	16+16	66	166-233
Pentium Pro/ Sixth	1995	64/32 bit	8+8	66	150-200
Pentium II/ Sixth	1997	64/32 bit	16+16	66	233-300
Pentium II/ Sixth	1998	64/32 bit	16+16	66/100	300-450
Pentium III/ Sixth	1999	64/32 bit	16+16	100	450-1.2GHz
AMD Athlon/ Seventh	1999	64/32 bit	64+64	266	500-2.2GHz
Pentium 4/ Seventh	2000	64/32 bit	12+8	400	1.4GHz-3.6GHz
AMD Athlon 64/ Eighth	2003	64/64 bit	64+64	400	2GHz-2.4GHz