Processor Core, Bus and PCI Bus clock speeds

Phil Storrs PC Hardware book

Processor Core, Bus and PCI Bus speeds

Intel Pentium® processors

Product code	Socket	Core clock speed	Bus clock speed	PCI Bus speed	Multiplier	Voltage
P60	5	60Mhz	60MHz	30MHz	1 times	5
P66	5	66Mhz	66MHz	33MHz	1 times	5
P54C-75	5	75Mhz	50MHz	25MHz	1.5 times	3.3 or 3.5
P54C-90	5	90MHz	60MHz	30MHz	1.5 times	3.3 or 3.5
P54C-100	5	100MHz	66/50MHz	33/25MHz	1.5/2.0 times	3.3 or 3.5
P54C-120	5	120MHz	60MHz	30MHz	2.0 times	3.3 or 3.5
P54C-133	5	133MHz	66MHz	33MHz	2.0 times	3.3 or 3.5
P54C-150	5	150MHz	60MHz	30MHz	2.5 times	3.3 or 3.5
P54C-166	5	166MHz	66MHz	33MHz	2.5 times	3.3 or 3.5
P54C-200	5	200MHz	66MHz	33MHz	3.0 times	3.3 or 3.5
P55C-166 MMX	5	166Mhz	66MHz	33MHz	2.5 times	2.8 & 3.3
P55C-200 MMX	5	200Mhz	66MHz	33MHz	3.0 times	2.8 & 3.3
P55C-233 MMX	5	233Mhz	66MHz	33MHz	3.5 times	2.8 & 3.3

The Core Clock Speed is the internal operating speed of the processor.
The Bus speed is the clock speed at which the processor addresses it's memory.
The PCI Bus Speed is the operating speed of the external PCI Bus slots
The multiplier is the multiplication factor between the Bus Speed and the Core Speed.
3.3 and 3.5 means the processor can operate on either voltage
2.8 & 3.3 means the processor needs two supply voltages

Intel Pentium® Pro processors

CPU core clock speed	Bus clock speed	Level 2 Cache size	PCI Bus speed	Multiplier
Pentium® Pro 150Mhz	60MHz	512K	30MHz	2.5 times
Pentium® Pro 180MHz	60MHz	256K	30MHz	3.0 times
Pentium® Pro 200MHz	66MHz	256K	33MHz	3.0 times
Pentium® Pro 200MHz	66MHz	1Meg	33MHz	3.0 times

Intel Pentium® II processors

CPU core clock speed	Level one Cache speed	Level two Cache speed	Bus clock speed	PCI bus speed
Pentium® II 233MHz	233Mhz	117MHz	66MHz	33MHz
Pentium® II 266MHz	266MHz	133MHz	66MHz	33MHz
Pentium® II 300HMz	300MHz	150MHz	66MHz	33MHz

Pentium Pro Processors use a Socket 8 and Pentium II Processors a Slot 1 connector. Socket 8 and Slot 1, have faster Data Buses to provide faster access to the Level 2 cache. Slot 1 is electrically identical to Socket 8 but uses an edge connector rather than a Pin Grid type socket.

Cyrix/IBM 6x86 processor

Product name	Socket	Core clock speed	Bus clock speed	PCI Bus speed	Multiplier	Voltage
6x86-P120+	5	100MHz	50MHz	25MHz	2.0 times	3.3 or 3.5
6x86-P133+	5	110MHz	55MHz *	27.5MHz	2.0 times	3.3 or 3.5
6x86-P150+	5	120MHz	60MHz	30MHz	2.0 times	3.3 or 3.5
6x86-P166+	5	133MHz	66MHz	33MHz	2.0 times	3.3 or 3.5
6x86-P200+	5	150MHz	75MHz #	37.5/33MHz	2.0 times	3.3 or 3.5
6x86MX PR150	7	150MHz	60MHz	30MHz	2.5 times	2.8 & 3.3
6x86MX PR200	7	166MHz	66MHz	33MHz	2.5 times	2.8 & 3.3
6x86MX PR233	7	200MHz	66MHz	33MHz	3.0 times	2.8 & 3.3

Note *: Requires a System Board that supports a 55MHz Bus Speed.
Note #: This processor requires a System Board that supports 75MHz Bus Speed.

AMD K5 processor

Product name	Socket	Core clock speed	Bus clock speed	PCI Bus speed	Multiplier	Voltage
K5 PR75	5	75MHz	50MHz	25MHz	1.5 times	3.3 or 3.5
K5 PR90	5	90MHz	60MHz	30MHz	1.5 times	3.3 or 3.5
K5 PR100	5	100MHz	66MHz	33MHz	1.5 times	3.3 or 3.5
K5 PR120	5	90MHz	60MHz	30MHz	1.5 times	3.3 or 3.5
K5 PR133	5	100MHz	66MHz	33MHz	1.5 times	3.3 or 3.5
K5 PR166	5	116.66MHz	66MHz	33MHz	1.75 times	3.3 or 3.5

AMD K6 processor (MMX enhanced)

Product name	Socket	Core clock speed	Bus clock speed	PCI Bus speed	Multiplier	Voltage
AMD-K6-166	7	166MHz	66MHz	33MHz	2.5 times	2.8 & 3.3
AMD-K6-200	7	200MHz	66MHz	33MHz	3 times	2.8 & 3.3
AMD-K6-233	7	233Hz	66MHz	33MHz	3.5 times	2.1 & 3.3
AMD-K6-266	7	266Hz	66MHz	33MHz	4.0 times	2.1 & 3.3
AMD-K6-300	7	300Hz	75MHz	37.5MHz	4.0 times	2.1 & 3.3

Supply voltages: Some System Boards may supply 2.9 volt rather than 2.8 volt. This will do no harm other than cause the Processor to run a bit hotter. The older processors that are listed as operating on 3.3 or 3.5 volt are coded STD if they operate on 3.3 volt, and VRE if they require 3.5 volt.
Note: Socket 7 is backward compatible with Socket 5.

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