System Clock

System board contains a clock that sets the beat for all activity on the board.

Rated in megahertz 1 mgHz = 1,000,000 beats

In rthe old days a system could only do one thing per beat. Now we have systems that can do two things.

If the CPU is faster than the motherboard can handle then we incorporate wait states. a single wait state for each 2 beats would be a 50% slowdown in processor speed. Set in BIOS. Change at your own risk...

CPU and Chip set

8088, 8086, 80286, 80386, 80486, Pentium

CPU Speed

Efficiency of programming code

Word Size (data Path Size) 16 to 64 bits (internal data size)

Data Path
largest number of bits that can be transported into the CPU (8 to 64 bits)

Maximum number of memory addersses
Address bus size - Minimum 1 megabyte max 4 gigabytes

CPU memory (cache
L1 or internal cache

Multiprocesing capability

Special functionality
mmx, RISC

We now measure CPU in terms of clock speed, bus speed, internal cache, and special functions.

Relating CPU Attributes to Bus Architecture

CPU attributes have to agree with bus attributes

address bus and data bus must have the same number of bits on the bus

Earlier CPUs Voltages

Early 486 processors ran on 5 volts. Later ran on 3.3. Some run on 2.8 volts which is created by a step down device on the motherboard. Documetnation will tell you how to set the jumpers for the lower voltage.

Coprocessors

Provided mathematical calucaltion capability that operated faster than the CPU could handle it. Coprocesors were the same chip without the math unit disabled.

Pentium and competitors

Pentiums have two math logic units. 64 bit external data path bit width and two 32 bit internal paths, one for each arithmetic unit.

memory or host bus operated at various speeds depending on the chip. 66, 75, 100, 133, 200.

Processor speed is the speed tht the procesor uses internally.

 

If the processor is operating at 100mHz and the bus speed is 75mHz than the CPU os operating twic as fast as the bus. This multiplier (X2) is usually set on teh motherboard. In reality bus speed is set, multiplier is set therefore the chip speed is a factor of the two numbers.

Memory Cache is a small amnount of SRAM that is much faster than normal DRAM. This memory is called L! cache or primary cache.There is also L2 cache also SRAM that is sometimes on the CPU sometime on the Motherboard.

Bus between the CPU and L2 is called the BACKSIDE BUS (frontside Bus is the system bus)

Classic Pentium

First, no longer manufactured. Had an error in the math unit.

16K - L1, no -L2, 66Mhz Bus speed, 60 - 200mHz processor speed

Pentium MMX

Targeted to the home market. Included extra code that processed multimedia code more efficiently

32k - L1, no - L2, 66 Mhz bus speed, 133 to 266 mHz processor speed

Pentium Pro

Designed for heavy server use. First Pentium to offer onboard L2 cache. Did not perform well withg old software (dos. win3.1) because it was designed for 32 bit processing and 32 bit code.

16k - L1, 256, 512, 1 MB - L2, 60 or 66 mHz bus speed, 150 to 200 mHz processor speed

Pentium II

Designed for graphics workstations. Used a slot 1 instead of a socket.

Celeron was a low end version tha twas targeted to home and low end business use.

The Xeon was targeted to high end servers and included the capability to support multiple processors on the motherboard (up to 8). This processor was recommended for Win NT, 2000, and Unix.

32k - L1, 256, 512 - L2, 66, 100 Bus speed, 233 - 450 mHz processor speed

Xeon - 32 K L1, 512, 1 or 2 MB L2, 100 mH bus, 400-450 Processor speed

Pentium III

New technology called SIMD (single instruction, multiple data) which was an extension of MMX. Will create significant improvements in multimedia processing once operating system and applications are written to support it. 133 mHz bus speed up to 1Ghz.

Slot 2 procesor

32K L1, 256, 512 L2, 100, 133 Bus, 400 - 1gH processor

Xeon 32K L1, 256 - 2MB L2, 100, 133 Bus, 500 - 866 Processor

Pentium IV

Back to socket type processor. Originally designed to work with RAMBUS technology to speed up access to RAM.

 

Pentium Competitors

AMD

Cyrix

Intel's Itanium

 

RISC

RISC chips contain fewer instructions on the chip itself. This makes for faster processing as long as the instructions are being processed. Used heavly in limited applications like video and other graphics appplications.

CPU Cooling fans

Must keep CPU below 185 degrees. SHould be between 90 and 110 degrees.

Might have variable speed and temperature monitors.

Large heatsinks are "cool"

Clean out the lint occassionaly.

CPU Form Factor

SEP - Single edge processor - early Celeron
SECC - Single Edge Contact Cartridge - Pentium II, Pentium III
SECC Version 2 - Pentium II, Pentium III
PPGA Plastic Pin Grid Array - Socket 370 - Celeron
FC-PGA - Pentium III

CPU Slots and sockets

There's a bunch of them.

CPU Voltage Regulator

Different chips run at different voltages. Important to read the documentation to determine what voltage to set on the motherboard. Some chips take care of it for you.

Chip set

Controls memory cache, external busses and some peripherals. Made by many companies:Intel, Cyris, VIA, VLSI and others.Operates as the interface between the fast system bus and the slower peripheral bus.Most use a hub topology that has a two speed interface where graphics and memory interface with the northbridge (or fast bus) versus the South Bridge that interfaces with the other external busses such as PCI, USB, IDE, etc.