COMPARISON BETWEEN INTEL 8085/8086, PENTIUM
AND CORE I-SERIES MICROPROCESSOR.

BRIEF DESCRIPTION OF THE LISTED MICROPROCESSORS

8085: The Intel 8085 written and pronounced (“eighty-eighty-five”) is an 8-bit microprocessor produced by Intel and introduced in March 1976. It is a conventional VON NEUMANN design based on the Intel 8080. Due to less internal circuitry, it is preferred when manufacturing less expensive microcomputer systems.

8086: Also called iAPX 86 is a 16-bit microprocessor chip designed by Intel between early 1976 and June
8, 1978, when it was released. It’s an enhanced version of the 8085 microprocessor. Because of the 8086 microprocessor, the x86 processor architecture became popular leading to a successful line of processor based off the same architecture.

A rare C8086 processor in purple ceramic DIP package with side-brazed pins.

Pentium: This is a brand used for a series of x86 architecture-compatible microprocessors produced by
Intel. The original Pentium was produced in 1993. After that the Pentium II and Pentium III were
released. The word Pentium is originally derived from the Greek word pente, meaning “five”.

Pentium sticker around 1993.

Intel Core Series Processor: Due to series of innovation in transistor technology, Intel was able to advance their microprocessor technology and launch it’s Pentium and Core Processor series. The major difference between these two processors was in their cache memory, where the Pentium processors were built with less cache memory making them suitable for light work and casual computer processes and the Core series with more cache memory and hyperthreading abilities. They are streamlined midrange consumer, workstation and enthusiast
computers central processing units (CPU).

BASIS OF COMPARISON

1. SIZE
8085: It’s an 8- bit microprocessor
8086: It’s a 16-bit microprocessor
Pentium 1: It’s a 32 bit microprocessor
Core i-series: It’s a 64 bit microprocessor

2. INSTRUCTION QUEUE
8085: Instruction queue is absent
8086: Instruction queue is present

3. PIPELINING:
8085: It does not support pipelined architecture.
8086: It supports pipelined architecture because of two independent units EU(execution unit) and BIU(Bus Interface Unit).
Pentium: It enables pipeline
Core series: It enables pipeline

4. ADDRESS BUS:
8085: It has a 16 bit address bus able to reference 2^16
8086: It has a 20 bit address bus able to reference 2^20
Pentium: It has a 32 bit address bus.
Core i3, i5, and i7: It has a 36bit address bus.

5. FLAGS:
8085: It has 5 flags (sign, zero, auxiliary, carry, and parity flag).
8086: It has 9 flags (overflow, direction, interrupt, trap, sign, zero, auxiliary ,carry and parity
flag).

6. MULTIPROCESSING SUPPORT:
8085: It does not support multiprocessing support.
8086: It supports multiprocessing support.

7. I/O:
8085: 8bit data bus can access 2^8 = 256 I/O.
8086: 16 bit data bus can access 2^16 = 65,536 I/O.

8. ARITHMETIC SUPPORT:
8085: It supports integer and decimal calculations only.
8086: It supports integer, decimal and ASCII arithmetic calculations.

Pentium: It performs arithmetic calculations.

Core Series: It performs the basic arithmetic, logical, control and input/output (I/O) operations .

9. MEMORY SEGMENTATION:
8085: The memory space is not segmented.
8086: The memory space is segmented.

10. MODE OF OPERATION:
8085: It has only one mode of operation.
8086: It has two modes of operation: maximum and minimum mode.
Pentium: It has two modes: protected mode and real address mode.
Core Series: It has 3 modes: Real mode, protected mode and SMM mode.

11. CLOCK SPEED:

8085: It has a clock speed of 3Mhz.

8086: It has a clock speed range of 5.8Mhz to 10Mhz.

Pentium: It has a clock speed ranging from 65Mhz(for the Plain Pentium Version) to 120–300Mhz for later versions of the Pentium line(Intel Pentium MMX).

Core series: It has a clock speed ranging from 2.20Ghz to 4.40Ghz.

12. TRANSISTORS USED:

8085: It was built with almost 6,500 transistors.

8086: It was built with almost 29,000 transistors.

Pentium: It makes use of about 3,100,000 transistors.

Core Series: It has 1.4 billion transistors in total.

13. MEMORY SIZE:

8085: It has memory size of 64KB.

8086: It has memory size of 1MB.

Pentium: It has memory size of 16GB.

Core Series: It has memory size ranging from 16GB to 128GB.

14. MEMORY TYPE:

8085: It’s an accumulator based memory type.

8086: It makes use of a General Purpose register memory type.

Pentium: It makes use of a DDR3 1066/1333 memory type.

Core Series: It makes use of DDR3 1066/1333 memory type.

OYEOKA ONYINYECHUKWU TENDERLY

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ELECTRONICS AND COMPUTER ENGINEERING

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