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Intel 8086

The Intel 8086 chip is almost identical to the 8088, except that it uses a 16-bit-wide data bus instead of the 8-bit bus of the 8088. It was actually invented before the 8088 but was not chosen for the original PC because IBM wanted to keep costs down by going with an 8-bit bus design.

The 8086 was used in some PC clones and later on in early IBM PS/2 models, but was never a popular choice for PCs. This is probably because by the time it started to be used, the 80286 was introduced, offering much improved performance over the 8086. The 8086 is architecturally identical to the 8088 aside from the wider data bus.

Note: The NEC V30 is an 8086-compatible but actually delivers slightly better performance due to a slightly more efficient internal design.

Note: Original designs were made in NMOS, newer ones in CMOS (80C86) for lower power consumption.

Look here for an explanation of the categories in the processor summary table below, including links to more detailed explanations.

General Information

Manufacturer

Intel

Family Name

8086

Code name

--

Processor Generation

First

Motherboard Generation

First

Version

8086

8086-8

8086-10

Introduced

June 1978

!?

Variants and Licensed Equivalents

80C86, AMD 8086, NEC V30

 

Speed Specifications

Memory Bus Speed (MHz)

4.77

8

10

Processor Clock Multiplier

1.0

Processor Speed (MHz)

4.77

8

10

"P" Rating

--

Benchmarks

iCOMP Rating

--

iCOMP 2.0 Rating

--

Norton SI

!?

!?

!?

Norton SI32

--

CPUmark32

--

Physical Characteristics

Process Technology

NMOS, CMOS

Circuit Size (microns)

3.0

Die Size (mm^2)

33

Transistors (millions)

0.029

Voltage, Power and Cooling

External or I/O Voltage (V)

5

Internal or Core Voltage (V)

5

Power Management

None

Cooling Requirements

None

Packaging

Packaging Style

40-Pin DIP

Motherboard Interface

DIP socket

External Architecture

Data Bus Width (bits)

16

Maximum Data Bus Bandwidth (Mbytes/sec)

9.1

15.3

19.1

Address Bus Width (bits)

20

Maximum Addressable Memory

1 MB

Level 2 Cache Type

None

Level 2 Cache Size

--

Level 2 Cache Bus Speed

--

Multiprocessing

No

Internal Architecture

Instruction Set

8088

MMX Support

No

Processor Modes

Real

x86 Execution Method

Native

Internal Components

Register Size (bits)

16

Pipeline Depth (stages)

1

Level 1 Cache Size

None

Level 1 Cache Mapping

--

Level 1 Cache Write Policy

--

Integer Units

1

Floating Point Unit / Math Coprocessor

Optional 8087 Coprocessor

Instruction Decoders

1

Branch Prediction Buffer Size / Accuracy

None

Write Buffers

None

Performance Enhancing Features

None

Next: Second Generation Processors


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