Intel 80486DX

The Intel 80486DX is a microprocessor made by Intel x86 family of processors. It is the successor to the Intel 80386 processor line.

Differences between the 80386 and 80486DX include:

• Data/Instruction Cache- An 8192-byte (8k) SRAM built into the processor core, designed to store the most commonly used instructions. The 386 supported an off-chip cache, but this was much slower.
• Pipelining- This allows the processor to handle a LocateFetchExecute each clock cycle. The pipeline is offset meaning the execute step required information from the previous two clock cycles. A locate would be to feed the next fetch, the fetch would be to feed the next execute. The 386 needs to do each step separately.
• Virtual Memory Handler- Hardwired programming to handle swapping memory to hard drive.
• Integrated FPU- Added accelerated high end math functions.

The 486 had a 32 bit data bus. This requires either 4 matched 30 pin simms or 1 72 pin simm

The 486 has a 32 bit address bus limiting it to a 4gb of ram.

The Early 486 machines often used VL bus for video cards and hard drives The bus speed matches the motherboard frequency.

See also: Intel 80486