Intel 386 (1985 - 1990)

The 386 signified a major increase in technology from Intel. The 386 was a 32-bit processor, meaning its data throughput was immediately twice that of the 286. Containing 275,000 transistors, the 80386DX processor came in 16, 20, 25, and 33 MHz versions. The 32-bit address bus allowed the chip to work with a full 4 GB of RAM and a staggering 64 TB of virtual memory. In addition, the 386 was the first chip to use instruction pipelining, which allows the processor to start working on the next instruction before the previous one is complete. While the chip could run in both real and protected mode (like the 286), it could also run in virtual real mode, allowing several reasl mode sessions to be run at a time. A multi-tasking operating system such as Windows was necessary to do this, though. In 1988, Intel released the 386SX, which was basically a low-fat version of the 386. It used the 16-bit data bus rather than the 32-bit, and it was slower, but it thus used less power and thus enabled Intel to promote the chip into desktops and even portables. In 1990, Intel released the 80386SL, which was basically an 855,00 transistor version of the 386SX processor, with ISA compatibility and power management circuitry.