8086 vs 80286 vs 80386 vs 80486: Microprocessor Differences

This article explores the differences between the Intel 8086, 80286, 80386, and 80486 microprocessors, building upon previous discussions of the 8085 architecture and programming instructions.

8086 Microprocessor

The 8086 was Intel’s successor to the 8085. Here are its key features:

• Data Bus Width: 16 bits
• Addressed Memory Size: 1MB

80286 Microprocessor

The 80286 improved upon the 8086 with these features:

• Data Bus Width: 16 bits
• Addressed Memory Size: 16MB
• Clock Speed: Higher, allowing some instructions to execute in as little as 250ns.
• Address/Data Bus: The 80286 features non-multiplexed address/data bus lines.

Figure 1: Pin diagrams of 8086 and 80286.

80386 Microprocessor

The 80386 marked a significant advancement with the following capabilities:

• Data Bus Width: 32 bits
• Memory Address: 32 bits
• Addressed Memory Size: Up to 4GB

There were also variations of the 80386:

• 80386SX: Addresses 16MB of memory.
• 80386SL: Addresses 32MB of memory.
• 80386SLC: Addresses 32MB of memory and includes internal cache memory for faster data processing.

Figure 2: Pin diagrams of 80386DX and 80386SX.

80486 Microprocessor

The 80486 further enhanced performance with these characteristics:

• Data Bus Width: 32 bits
• Address Bus: 32 bits
• Memory Size: 4GB + 16KB cache
• Instruction Execution: Approximately half of the instructions were executed in 1 clock cycle instead of two.
• Integrated Coprocessor: Included an 80386-like microprocessor and an 80387-like numeric coprocessor.

Comparison Table: 80286 vs 80386 vs 80486