Karbosguide.com - Module 3a1.

About CPUs


To understand the data processing methodology, an understanding of the design and function of the CPU is essential. The following subjects will be covered on these pages.

The contents:

  • What is a CPU?
  • Intro to CPUs from 1st to 7th generation
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  • The module is divided in several sub modules, which all together ought to be read as a unit.


    What is a CPU?

    The CPU is certainly the most important PC component. CPU stands for Central Processing Unit. Let us briefly study that name:

  • It is a processor, because it processes (moves and calculates) data.
  • It is central, because it is the center of PC data processing.
  • It is a unit, because it is a chip, which contains millions of transistors.

    Speed, speed, speed

    Without the CPU, there would be no PC. Like all other hardware components, the CPUs are continually undergoing further development. You can see the explosive technological development in data processing most clearly in the development of newer and faster CPUs. The CPUs have for years doubled their performance about every 18 months (Moore's Law), and there are no indications that this trend will stop.

    When we now look at all the CPUs from a broader perspective, we can see that:

  • The CPU history is closely tied to the companies IBM and especially Intel.
  • The CPUs have their roots back to Intel's chip 4004 from 1971.
  • You can identify seven or eight CPU generations up till today.
  • The compatibility concept has been important throughout the development.


    CPUs - brief review

    CPU history starts in 1971, when a small unknown company, Intel, for the first time combined multiple transistors to form a central processing unit - a chip called Intel 4004. However, it was 8 years before the first PC was constructed.

    PCs are designed around different CPU generations. Intel is not the only company manufacturing CPUs, but by far the leading one. The following table shows the different CPU generations. They are predominantly Intel chips, but in the 5th generation we see alternatives:

    PC CPUs Year
    Number
    of transistors
    1st. Generation 8086 and 8088 1978-81
    29,000
    2nd. Generation 80286 1984
    134,000
    3rd. Generation 80386DX and 80386SX 1987-88
    275,000
    4th. Generation 80486SX, 80486DX,
    80486DX2 and 80486DX4
    1990-92
    1,200,000
    5th. Generation Pentium
    Cyrix 6X86
    AMD K5
    IDT WinChip C6
    1993-95
    1996
    1996
    1997
    3,100,000
    --
    --
    3,500,000
    Improved
    5th. Generation
    Pentium MMX
    IBM/Cyrix 6x86MX
    IDT WinChip2 3D
    1997
    1997
    1998
    4,500,000
    6,000,000
    6,000,000
    6th. Generation Pentium Pro
    AMD K6
    Pentium II
    AMD K6-2
    1995
    1997
    1997
    1998
    5,500,000
    8,800,000
    7,500,000
    9,300,000
    Improved 6th. Generation Mobile Pentium II
    Mobile Celeron
    Pentium III
    AMD K6-3
    Pentium III CuMine
    1999
    27,400,000
    18,900,000
    9,300,000
    ?
    28,000,000
    7th. Generation AMD original Athlon
    AMD Athlon Thunderbird
    Pentium 4
    1999
    2000
    2001
    22,000,000
    37,000,000
    42,000,000

    Please notice that the mobile CPUs as well as Pentium III CuMine include very large on-die L2-caches. These caches consist of millions of transistors.

    We will now see what the CPU really does.


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    Learn more

    Click for Module 3b about CPU improvements

    Click for Module 3c about the 5th generations CPUs (Pentiums etc.)

    Click for Module 3d about the clock frequencies

    Click for Module 3e about 6th generations CPUs (Pentium IIs etc.)

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