California Local Gov. Retention Guidelines and Other Free Books	White Papers	Archive Builders Home Page	Site Summary Sheet	Entire Site In One PDF File
Available and Past Courses	Copies of Presentation Handouts	Upcoming and Past Presentations	For Questions About the Industry	Site Revision History

This is version 22016v010 of this document. Click here to access the most recent version of this document.

Evolution of Intel Microprocessors: 1971 to 2003

MHz (MegaHertz) (Millions of processor cycles per second) The number of times the processor goes through one cycle. The start of a processor cycle is determined by a pulse (tick) from the processor’s clock.

GHz (GigaHertz) (Billions of processors cycles per second). 1 thousand MHz = 1 GHz

MIPS: (Millions of Instructions per Second) with the introduction of the 80486 DX2, parallel instruction execution increased the number of instructions executed per processor cycle to approximately one instruction per cycle. Parallel instruction execution requires many more transistors, so the increase in the number of transistors has increased the number of instructions that can be executed per second faster than the clock cycle speed has increased. A larger transistor budget allows the addition of specialized instructions, which increase the microprocessor’s speed in processing specialized information such as graphics by increasing the amount of information processed per instruction.

GIPS (GigaInstructions per Second) Billions of instructions per second. 1 thousand MIPS = 1 GIP Design Rule: because the wires and components, including transistors, on chips are drawn photographically, the pixel size of the imaging process determines the width of the wires and the size of the transistors. The size of the transistors determines how many will fit on a chip of a given size. (The optimal size of a chip depends on the chip manufacturing processes. In general, chip size increases slowly over time.) The smaller the transistors, the more will fit on the chip, determining the chip’s transistor budget. The size of the transistors also determines the transistor’s switching speed. Smaller transistors switch faster. One micron is one one-millionth of a meter or about 40 millionths of one inch. Finally, the power required to switch smaller transistors is less, so smaller pixels in the design rules allow the batteries in laptop computers to last longer.

Number of Transistors: The number of transistors increases as the square of decrease in design rule size. Each reduction in design rule size is chosen to about double the number of available transistors (the transistor budget). [For example: (.25micron / .18 micron) x (.25 / .18) = 2.] The gradual increase in die size (the size of the chip) also increases the number of transistors.

Address Bus Bits: The address bus width in bits is based on the microprocessor chip family. (In the later chips of the 80686 family, some changes have been made to make more memory addressable under special circumstances, by using 36 bits to address 16 times as much memory as is possible with 32 address bits, but the generalized addressing structure is still 32 bits.) Each time a bit is added to the address bus width, the amount of memory (RAM: Random Access Memory) that can be addressed is doubled. 4 bit addresses allow the addressing of 16 bytes of memory (and extra work is necessary to address 256 bytes of memory). 8 bits allow the addressing of 256 bytes of memory (and extra work is necessary to address 65,536 bytes of memory). 16 bits can address 65,536 bytes of memory. 32 bits can address 4,294,967,296 bytes of memory (about 4 billion bytes). As memory prices drop, it becomes necessary to address over 4 billion bytes of memory. The 80786 family is due out from Intel in the year 2000. It will have a 64 bit address bus and will be able to address over 16 billion billion (16 quintillion) bytes of memory.

See also: http://www.intel.com/intel/intelis/museum/ Intel’s history of the microprocessor.

California Local Gov. Retention Guidelines and Other Free Books	White Papers	Archive Builders Home Page	Site Summary Sheet	Entire Site In One PDF File
Available and Past Courses	Copies of Presentation Handouts	Upcoming and Past Presentations	For Questions About the Industry	Site Revision History