MICROPROCESSOR

Microprocessor

The processor, also known as the CPU, can be thought of as the brains of the system and is responsible for executing software commands and performing calculation functions. The following table shows the features of the various Intel processors.
CPU Terminology
This page contains a CPU definition/terminology list to help you understand the world of microprocessors.

CPU – Central Processing Unit. Also known as a processor or microprocessor, the CPU is the brains of a computer. It’s responsible for executing computer instructions, and is one of the most important elements in a computer.

Clock Speed – Also known as clock rate, the clock speed is the rate at which a processor executes operations. The higher the clock speed, the more operations is it can perform. Measured in MHz or GHz.

Assembly – The native language of a microprocessor. Each CPU has its own specific assembly language.

GHz – Gigahertz. A unit of frequency that is equal to one billion cycles per second. A CPU’s clock speed is usually measured in gigahertz.

ALU – The ALU (Arithmetic and Logic Unit) is the part of a processor that performs the actual computations of data.

Data Width – The width of the ALU. An 8-bit ALU can perform operations on two 8-bit numbers, while a 32-bit ALU can operate on 32-bit numbers. An 8-bit ALU would have to execute four instructions to add two 32-bit numbers, while a 32-bit ALU would be able to do it in one instruction.

MIPS – Stands for millions of instructions per second, used as a rough indication of the performance of a CPU.

Overclocking – Forcing a CPU to run at a higher clock speed than listed on the manufacturers specification. Overclocking a CPU increases its performance, although it can result in system instability and may cause damage to the CPU.

Transistors – Miniature electronic switches that make up a processor. The number of transistors available has a large impact on the performance of a processor.


Intel – World leading CPU manufacturer, in competition with AMD.

Pentium – A widely-used brand family of processors made by Intel.

Celeron – Intel’s budget line of processors, the Celeron is suited for basic computer use.
Dual-core – A dual-core CPU is one made up of two independent processors combined onto a single integrated circuit, or silicon chip.

AMD – Stands for Advanced Micro Devices. A world leading CPU manufacturer, competing with Intel.

Athlon – A brand family of modern processors made by AMD.

Athlon 64 – AMD’s entry into the consumer 64-bit processor market, the AMD Athlon 64 is a current breed of CPUs based on AMD64 architecture.

Athlon 64 X2 – The first dual-core desktop CPU made by AMD. It’s essentially made up of two Athlon 64 cores, resulting in a faster processor.

Athlon XP – A type of AMD Athlon processor, with the XP meaning ‘extra performance’. Production of Athlon XP processors has discontinued with the introduction of the Athlon 64.

Sempron – AMD’s budget processor model, the Sempron goes head to head with the Intel Celeron in the budget CPU market.

SIMD: Single instruction multiple data; a general term for using a single CPU instruction to perform the same operation on many (2, 4, 8, 16 etc.) data items all done at once. SIMD is very useful in multimedia (audio and video) and 3D games, where lots of data is operated on in the same manner.

MMX: officially means nothing, (Intel trademarked term), but some have called it matrix math extensions or multimedia extensions. Simply put it is a group of low level instructions that process 64-bit SIMD integer data. For example, four 16-bit integers could be added at once. (Added in Pentium w/ MMX and Pentium II)

SSE: Streaming SIMD Extensions (Intel term); a new group of SIMD instructions that operate on 128-bit SIMD data, mostly groups of four 32-bit floating point data items. (Added in Pentium III)

SSE2: Streaming SIMD Extensions 2 (Intel term);a new group of SIMD instructions that operate on 128-bit SIMD data, mostly groups of two 64-bit floating point data and 2 (64-bit), 4 (32-bit), 8 (16-bit) or 16 (8-bit) integers. (Added in Pentium 4)

3DNow: AMD term for SIMD instructions that operate on two 32-bit floating point data items at once. The 3D comes from the fact that three dimension processing (popular in games) requires the use of lots of floating point calculations. (Added in K6-2)

3DNow Pro: AMD term for SSE. (Added for Athon XP)

FSB: Front Side Bus. The bus that connects the CPU to the Northbridge chip. Typically runs at 100 Mhz or 133 Mhz. On the Pentium 4 it runs at 100 Mhz (now 133 Mhz) but sends data 4 time per clock, thus it is said to be 400 Mhz or 533 Mhz.

Integer: positive and negative whole numbers. An 8-bit signed integer, for example, can range from -128 to +127. An 8-bit unsigned integer can range from 0 to 255.

Floating point: A numeric representation where numbers can have a decimal point and an exponent (similar to scientific notation), such as 3.5 x 10^5 (three point five times ten to the fifth power). The decimal point is said to be "floating" since its position can vary (mathematically), unlike in integers where it is always in the rightmost position.

Cache: because memory operates very slow compared to CPUs, CPUs keep copies of recently used memory in a much faster (and expensive) memory closer to the CPU called a cache. The L1 (level one) cache is smaller and faster than the L2 (level two) cache. Typically the L2 cache contains both code and data, but the L1 cache has two parts, an L1 code cache and an L1 data cache. L1 caches can be 10-20 times faster than memory, L2 caches about 3-5 times faster.

Heat sinksWith the increase of performance, heat has become a big issue with computer processors and other advanced peripherals. If your computer processor is a Pentium 66MHz or faster processor, it is highly recommended that you ensure it has a heat sink for the CPU
There are two types of heatsinks which are an Active and Passive heatsink.
The Active heatsinks utilize power and are usually a fan type or some other peltier cooling device. its a fans with ball-bearing motors which generally last much longer than sleeve bearings.
The Passive heatsinks are 100% reliable, as they have no mechanical components. Passive heatsinks are made of an aluminum-finned radiator that dissipates heat through convection.

THERMAL COMPOUND

Thermal compound (heatsink jelly, heatsink compound, thermal gunk, silicon compound) is a sticky paste which is placed directly onto the CPU. This compound allows for the heatsink to placed directly to the CPU. This material is used to prevent air gaps from forming between the CPU and heatsink which can cause poor heat conductivity.
***** While the thermal compound does not conduct electricity and your motherboard should work fine if any is spilt onto it


Chip Characteristics

Processor Speed (MHz) Heat Sink Cooling Fan Cache Package Pins
8088 5-8 No No No DIP 40
80286 6
10
12 No No No LLC
PGA
PLCC 68
80386SX 16 - 33 No No No PGA 100
80386DX 16 - 33 No No No PGA 100
80486SX 16 - 33 No Yes on 33 MHz 0-256K PGA 100
80486DX 25 - 50 No Yes on 33 MHz 0-256k PGA
SQFP 168
208
Pentium 60-166 Yes Yes 256-512k PGA 296
Pentium Pro 233-266 Yes Yes 256k-1mb PGA 387
Pentium II 233-500 Yes Yes 512k SEC 242
Pentium III 450mhz-1.13ghz Yes Yes 256-512k SEC/PGA 242/370
Pentium IV 1.30-3.20ghz Yes Yes 256-512k PGA 423/478
Itanium 733-833mhz Yes Yes 96k PAC 418
Itanium II 900mhz-1.0ghz Yes Yes 256k OLGA 611

• With the Pentium MMX processors, 57 multimedia specific instructions were added to increase multimedia performance and increased the L1 cache size to 32KB.
• The Pentium Pro added Dynamic Execution and increase L2 cache to 512KB.
• The Pentium II had integrated MMX technology and used a new Single Edge Contact Cartridge(SEC).
• The Pentium III provided increased processor speeds, a 100mhz front size bus speed and increased L2 cache to 512KB.
• The Celeron processors are less expensive but only have a 66mhz bus and 128KB L2 cache.
• The Pentium IV introduced a number of graphics enhancements. 2 versions were made - The first was a 423-pin PGA package with 256 KB L2 cache. The second version offers a 478-pin PGA package with 512 KB of L2 cache.
• Intel Xeon processors are higher-end and based on their Pentium II, III and IV counterparts.
Bus Sizes of CPU’s

Processor Register Data Bus Address Bus
8088 16-bit 8-bit 20-bit
80286 16-bit 16-bit 24-bit
80386SX 32-bit 16-bit 24-bit
80386DX 32-bit 32-bit 32-bit
80486SX 32-bit 32-bit 32-bit
80486DX 32-bit 32-bit 32-bit
Pentium 64-bit 64-bit 32-bit
Pentium Pro 64-bit 64-bit 36 bit
Pentium II 64-bit 64-bit 36 bit
Pentium III 64-bit 64-bit 36 bit
Pentium IV 64-bit 64-bit 36 bit
Itanium 64-bit 64-bit 44 bit
Itanium II 64-bit 128-bit 44 bit


While Intel holds the majority of the processor market share, companies such as AMD have been producing clones based on the X86 architecture. The table below outlines the various socket/slot types and the processors that they support.
Socket Pins Processor
Socket 4 237 PGA Pentium 60/66, Pentium Overdrive
Socket 5 320 PGA Pentium 75-133, Pentium Overdrive
Socket 7 321 PGA Pentium 75-200, Pentium Overdrive
Socket 8 387 PGA Pentium Pro
Slot 1 242 SEC/SEPP Pentium II, Pentium III, Celeron
Slot 2 330 SECC-2 Xeon
Super Socket 7 321 PGA Pentium MMX, Pentium Pro, AMD K6-2, K6-2+, K6-3, K6-3+
Socket 370 370 PGA Celeron, Pentium III, Cyrix III
Socket 418 418 PAC Itanium
Socket 423 423 PGA Pentium IV
Socket 478 478 PGA Pentium IV
Socket 603 603 PGA Pentium IV-based Xeon, Xeon MP
Socket 611 611 OLGA Itanium II
Socket 940 micro-PGA AMD Opteron
Socket A 462 PGA AMD Athlon, Athlon XP, Duron
Slot A 242 Slot A AMD Athlon

Pentium:

Pentium is the fifth-generation x86 architecture microprocessor released by Intel Corporation in 1993.
It succeeds the 486 processor. Though it was named as Pentium this chip was actually to be named 80586 or i586.

Intel first introduced the Pentium in two versions: 60MHz and 66MHz. The 60MHz version though it works fine, it was slow & didn't quite pass the 66MHz quality-control cut. Hence 66MHz version was released.

Pentium has 3.1 million transistors, which use a 32-bit address bus, 64-bit data path, 16K on-chip cache and it has speed, which varies from 60MHz to 200MHz.

The processor is a combination of two 486DX chips in one larger chip. The advantage of this architecture is that each chip can execute instructions independent of each other. This type of parallel processing ability is called super scalar.

Pentiums require special motherboards, because they run significantly hotter than previous processors. They require a heat sink on top of the processor to absorb and ventilate the heat.
Some of the other important changes Pentium had from the 486 are:
Superscalar architecture - The Pentium has two data paths that let it complete multiple instructions per clock cycle. The architecture has two pipes called "U" and "V". Pipe "U" can execute any instruction whereas the pipe "V" handles simplest instructions.
64-bit data path - Assists in extracting double the amount of information from the memory on each fetch when compared to 32 bit data paths.

MMX instructions- This technology contains SIMD instruction set designed to use in multimedia applications.

Manufacturing process 0.8 micron BiCMOS process , 3.1 million transistors
Data bus width 32 (64 bit data bus) bit
Package 273-pin ceramic Pin Grid Array2.16" x 2.16" (5.49 cm x 5.49 cm)
Speed (MHz) 60 MHz
Specification numbers Q0352 Q0394 Q0400 Q0412 Q0466 Q0625 SX753 SX835 SX948 SX974 SZ949
Physical memory (GB) 4 GB
Level 1 cache size 8 KB code and 8 KB write-back data
Floating Point Unit Integrated
ICOMP index 510
V core (V) 5 ± 5%There was a version of Pentium 60 with 5.15 - 5.4 core voltage. Please follow links with processor's specification numbers for more accurate information.
Min/Max operating temperature (°C) 0 - 70/75/80/85 (Depends on a processor specification number). Please follow links with processor's specification numbers for more accurate information.
Upgrade options Pentium overdrive 133


Pentium Pro

is a sixth-generation x86 architecture microprocessor built with an intention of replacing the original Pentium.was designed to meet the needs of a server and fit in a rectangular Socket 8 form factor. Runs at speeds up to 200MHz, in a 32-bit operating system environment using "dynamic execution".
was integrated with 256KB, 512 KB or 1 MB L2 cache running at the processor speed and the clock speeds were 150, 166, 180 or 200 MHz with a 60 or 66 MHz external bus clock.
often ran slower than a Pentium while running on 16-bit code and operating systems. This caused the chip to fail in home PC market, as most common operating systems were 16-bit (Windows 3.1) and some parts of Windows 95 itself were still mostly 16-bit.
The below mentioned enhancements are available in Pentium Pro:
Multiprocessor support up to 4 processors.
Two low-power states: Auto-HALT and Stop-Grant.
Optimized for 32 applications.
Integrated non-blocking second level cache that runs at the speed of the processor.
An exclusive internal bus for level 2 caches.
Separate 8 KB code and 8 KB data level 1 cache.

Pentium II

After the Pentium I, the fastest Intel processor available was the Pentium II. Introduced in 1997, the speeds for this processor range from 233MHz to over 400MHz.

It was designed for Multimedia applications with special on-chip multimedia instructions and high-speed cache memory.
Pentium II was packaged in a slot-based form-factor instead of a socket one, unlike previous makes of Intel processors; thereby allowing Intel to separate the secondary cache from the processor; though still keeping it on a closely coupled bus. The separate cache was comparatively slower (i.e., ran at half the processor speed) than in the Pentium Pro but was not expensive.

The Pentium II uses a Single Edge connector (SEC) to attach to the motherboard instead of the standard PGA package that was used with the earlier processor types. The processor is on a card that can be easily replaced.

The original Klamath Pentium II ran at 233 and 266 MHz; thereby producing high quantity of heat. It was designed with a 66 MHz front side bus that was inadequate for the CPU's design to show its full potential. A 300 MHz version was released during 1997
During 1998, the Deschutes core Pentium IIs got released that ran at 333 MHz and hence were very much cooler. With the support for 100 MHz FSB speeds, there was quite a decent improvement in performance. Also, during the above period, Pentium IIs that ran at 266, 300, 350, 400, and 450 MHz were also released

Celeron

Celeron was a low-end version of the Pentium II. It might be called a Pentium II with less (or no) level 2 cache. Pentium II was designed to be used in PC's. However, Pentium II Xeon was a high-end version that was based on the same Pentium II circuitry with the intention of using it on multiprocessor severs and workstations.

Pentium III

is x86 based architecture microprocessor introduced by Intel in 1999.
is similar to Pentium II, the major difference being the addition of SSE instructions.
included 70 new instructions and was optimized for voice recognition and multimedia.
aside from faster speeds, one of the significant features of the Pentium III was the PSN (processor serial number), a unique number electronically encoded into the processor.
SSE (Streaming SIMD Extensions) is a technology introduced to add better floating point support (128 (4X32) bit registers) to cater to growing Graphic card demands.
The Pentium III was replaced by the new Pentium 4 series. Pentium M is an improvement on the Pentium III design.

Katmai

Pentium III Katmai is a Sample, which is still labeled as a Pentium II built on a 0.25 µm process. The initial Katmai was very much similar to the Pentium II. The only differences being the introduction of SSE and an improved L1 cache controller. It was initially released at speeds of 450 and 500 MHz. Later on it was released at 550 MHz and 600 MHz. It used the same slot that was designed for Pentium II.

Katmai specifications are given in the next page.

Data bus width 32 (64-bit data bus) bit
Package Single Edge Contact Cartridge (SECC)
Socket Slot 1 (SC242)
Speed (MHz) 400
Bus frequency (MHz) 100
Low power features Auto-HALT state, Stop Grant state, Sleep state, Deep Sleep state & System Management Mode
Other features MMX technology & SSE instructions
Level 1 cache size 16 KB instruction cache
16 KB data cache
Level 2 cache size Half-speed in-package 512 KB
Floating Point Unit Integrated
Min operating temperature (°C) 0
Clock rate 450-600 MHz
- 100 MHz FSB: 450, 500, 550, 600 MHz
- 133 MHz FSB: 533, 600 MHz (B-models)
Front side bus 100, 133 MHz

Copper mine

The second version of Pentium III core is called Coppermine. It was released in 1999 with an integrated full-speed 256 KB L2 cache with lower latency. This improved its performance over

Katmai.

Built on a 0.18 µm process, Pentium III Coppermines ran at speeds of 500, 533, 550, 600, 650, 667, 700, and 733 MHz. Pentium IIIs that ran at speeds of 750, 800, 850, 866, 900, 933 and 1000 MHz (1GHz) were released by Intel during the mid 2000.
Coppermine specifications are given on the next page.

Data bus width 32 (64-bit data bus) bit
Socket Slot 1 (SC242)
Speed (MHz) 600
Bus frequency (MHz) 133
Specification numbers SL3H7 SL3NB SL3XJ
Low power features Auto-HALT state, Stop Grant state, Sleep state, Deep Sleep state & System Management Mode
Other features MMX technology & SSE instructions
Level 1 cache size 16 KB instruction cache
16 KB data cache
Level 2 cache size Full-speed on-die 256 KB
Floating Point Unit Integrated
Min/Recommended/Max V core (V) 1.57 / 1.65 / 1.69
Min/Max operating temperature (°C) 0 - 82
Min/Max power dissipation (W) 4.23 (Stop Grant mode) / 21.45
Front Side Bus 100, 133 MHz
Clock rate 550 - 1133 MHz
- 100 MHz FSB: 550, 600, 650, 700, 750, 800, 850, 900, 1000, 1100 MHz (E-Models)
- 133 MHz FSB: 533, 600, 667, 733, 800, 866, 933, 1000, 1133 MHz (EB-Models)

Coppermine-T

The third version, Tualatin (Coppermine-T), released during 2001, was just a trial for Intel's new 0.13 µm process. It was basically intended for servers where power consumption matters the most. The performance of Tualatin was quite well, especially with variations that had 512 Kb L2 cache (called the Pentium III-S). The speeds reached 1.0, 1.13, 1.2, 1.26, 1.33 and 1.4 GHz till early 2002.
Data bus width 32 (64-bit data bus) bit
Socket Slot 1 (SC242) , Socket 370
Speed (MHz) 933
Bus frequency (MHz) 133
Specification number SL4BT
Low power features Auto- HALT state, Stop Grant state, Sleep state, Deep Sleep state & System Management Mode
Other features MMX technology & SSE instructions
Level 1 cache size 16 KB instruction cache
16 KB data cache
Level 2 cache size Full-speed on-die 256 KB
Floating Point Unit Integrated
Min/Recommended/Max V core (V) 1.62 / 1.7 / 1.74
Min/Max power dissipation (W) 4.35 (Stop Grant mode) / 30.09
Clock rate 866, 933, 1000, 1133 MHz
Front Bus side 133 Mhz

Pentium 4

Introduced during end 2000 had 1.4 and 1.5GHz clock rates, featuring the NetBurst micro-architecture. Firstly, a 400MHz system bus (FSB) came in and later on this evolved to 533 and 800MHz.
Contained 42 million transistors. It was initially built with 180 nanometers process technology and then moved on to 130 and 90.
The first chipset for Pentium 4 supported Rambus memory only; whereas the chipsets that followed supported the more common DDR SDRAM.

Willamette

Willamette, the first Pentium 4 with the initial 1.3, 1.4 and 1.5GHz was released in competition to AMD Athlon. The core was produced using a 0.18 micrometer (180 nm) process and initially utilized socket 423 on motherboards. However, the later revisions moved on to socket 478. Though reasonably priced it was handicapped by the requirement of relatively expensive Rambus Dynamic RAM (RDRAM ). Pentium III was retained as Intel's top selling chip. Athlon also sold somewhat better than Pentium 4.
The first P4 to provide a tough challenge to its rival Athlon Thunderbird was the 2.0 GHz.

Northwood

The new Pentium 4s by Intel with new Northwood core at 2.0 and 2.2 GHz got released in January 2002.
Northwood had an increase in the secondary cache size from 256k to 512k (transistor count increased from 42 million to 55 million) had a transition to a new 0.13 micrometer (130 nm) fabrication process with a new socket, socket 478.
Chips were capable of running at the same speed producing less heat, or even run at higher clocks when the chip was made out of smaller transistors.
In April 2002 a 2.4 GHz P4 was released which was followed by a 2.53 GHz part in May (the bus speed was increased from 400MHz to 533MHz), 2.6 and 2.8 GHz parts in August, and a 3.06 GHz Pentium 4 in November. The P4s in the 2.4 to 2.8 GHz range were definitely the fastest chips available in the market.
Mainly the difference in all these new versions was that they all supported Hyper -Threading , and ran their system buses at 800 MHz.
Hyper-threading was supported by the 3.06 GHz processor thus enabling multiple threads to be run together. This could be attained by duplicating some parts of the processor and letting the operating system feel that there are two logical processors. This was present in all Northwood CPUs. But for the 3.06GHz model, this was disabled in the core in the rest of it.
The outcome of over-clocking Northwood cores resulted in a startling phenomenon. The processor was close to dead when VCore was pushed past 1.7v. From then on this incidence was called "NDS" or Northwood Death Syndrome.
Although Bus frequency on a Northwood is 100 MHz, because the processor uses Quad Data Rate bus the effective bus speed is 400 MHz.
Manufacturing process 0.18 micron
Data bus width 32 bit
Socket Socket 423 (PGA423)
Speed (MHz) 1400
Bus frequency (MHz) 100
Specification numbers SL4SC SL4SG
Low power features System Management Mode, Auto-HALT mode, Stop Grant mode, Sleep mode & Deep Sleep mode
Other features SSE2
Level 1 cache size Execution trace cache holds 12K micro-operations
8 KB data cache
Level 2 cache size 256 KB 8-way associative full-speed on-die cache
Floating Point Unit Integrated
V core (V) 1.7
Min/Max operating temperature (°C) 5 - 70
Min/Max power dissipation (W) 16.66 (Stop Grant mode) / 66.18

The Pentium 4 Extreme Edition (P4EE) announced in September 2003, was aimed at gamers, nicknaming it the "Emergency Edition". This was like Pentium 4 i.e., it would run in the same motherboards, but the difference was an addition of a 2 MB of Level 3 cache. It was twice as fast as that of the Xeon MP in a socket 478 form factor with an 800MHz bus.
A minimal increase in the performance in late 2004 was observed when the bus speed was increased from 800MHz to 1066MHz. The features of the new 3.73GHz Extreme Edition was similar to that of a 6x0-sequence Prescott, but with a 1066MHz bus. However performance wise, the 3.73GHz Extreme Edition was mostly found to be slower than the 3.46GHz version.
On February 1, 2004, Intel launched Pentium 4 "Prescott." For the first time, the core has a 90nm process, and it is also a major reworking of the Pentium 4's micro architecture. Northwood runs slightly faster than a Prescott although a Prescott clocked at the same rate as a Northwood. At present, the fastest Prescott-based processor is 3.8 GHz.
On release, the Prescott generated approximately 60% more heat clock-for-clock compared to Northwood. With a shift in socket type, from Socket 478 to LGA775 the average temperatures were slightly lowered.
The thermal problems were so severe that a decision to abandon the Prescott architecture altogether was taken by Intel. Plans for 4GHz processors were stalled by Intel in favor of dual core processors.
Dual Core

Three mainstream dual-core variants of Pentium 4 are in the pipeline. Intel has the intentions of having a 60-80% increase in performance per clock-speed and it is likely to be marketed as

Pentium D. These chips are proposed to be launched in late 2005.
The Pentium-D processors would actually be two connected Prescott cores. The consumption of power is estimated above 130 watts. The 1066 MHz bus is the main difference between the EE edition of P-D and the other mainstream models along with retaining the Hyper Threading technology for each core.