Clock Multipliers Table

This table contains the driving clock speeds and the clock multipliers for AMD/Cyrix/Intel processors

brand	CPU name- rated speed	internal speed [Mhz]	multiplier	clock (mem bus) [Mhz]	PCI bus [Mhz]	Notes/P-rating
Intel/AMD/Cyrix 486 Class	486DX2-66	66	2x	33	33
	486DX2-80	80	2x	40	40?	?
	Cx486DX4-75	75	3x	25	?
	486DX4-100	100	3x	33	33
AMD Enhanced 486 Class	486DX4-120	120	3x	40	40?	?
	486DX4-120	100	2x	50	?	2x mode (non-standard)
Intel Pentium®	Pentium®-75	75	1.5x	50	25
	Pentium®-90	90	1.5x	60	30
	Pentium®-100	100	1.5x	66	33
	Pentium®-120	120	2x	60	30
	Pentium®-133	133	2x	66	33
	Pentium®-150	150	2.5x	60	30
	Pentium®-166	166	2.5x	66	33
	Pentium®-200	200	3x	66	33
AMD 5x86	Amd5x86-133	133	4x	33	33	P75+
	Amd5x86-133	160**	4x	40	40*?	P100+(non-standard)
	Amd5x86-133	150**	3x	50	50*?	n/a (non-standard)
Cyrix 5x86	Cx5x86-100	100	2x/3x	50/33		P75+
	Cx5x86-120	120	3x	40		P90+
Cyrix 6x86	Cx6x86-100	100	2x	50	25*	P120+
	Cx6x86-110	110	2x	55	?	P133+
	Cx6x86-120	120	2x	60	30*	P150+
	Cx6x86-133	133	2x	66	33*	P166+
	Cx6x86-150	150	2x	75	40*	P200+
NexGen	Nx586-80?	I couldn't find any info on this processor
Notes	* are my speculations. ** are overclocked modes. (may damage the CPU, see Overclocking FAQ). Cyrix 486DX4, 5x86 and 6x86 have 2x/3x clock multiplier. Amd 5x86 has 3x/4x clock multiplier. PCI specs are for 33Mhz; dunno if or how PCI stands overclocking to 40 or 50 Mhz. Only Intel Pentium®s and Cyrix 6x86 have triple clocks (internal/memory/PCI bus). For the others the PCI clock is the same as the memory clock, if not forced to 33 Mhz.