Intel and compatable CPU's Programming Information
The 80386 initially shipped at 16 MHz in October 1985, making it faster than any Intel version of the 80286. Note, some others had overclocked 286 Processers up to 20Mhz.
The first IBM compatible to use the 386 was the Compaq 386,
The 80386 had a MIPS (million instructions per second) rating of 5 (at 16 MHz) to 11.4 (33 MHz). This is an average of 0.33 MIPS per MHz of clock speed.
<Byte magazine May93>
This indicated the 386 is up to 50% more powerful than the 0.21 MIPS/MHz rating of the 80286, although MIPS is not always a reliable pedictor of CPU performance.
It did not require special EMS memory boards to expand
MS-DOS memory limits like the 80286 did. With the 386, the EMS standard can be
simulated in normal extended memory, and many DOS add-ons
provide this "Expanded Memory Manager" feature.
This was the first X86 processor that could eliminate the 64K memory segmentation issued that programmers had to deal with
Some of the first operating systems to support the 386 processor was Bill Jolitz's 386BSD, BSDI's BSD386, Bill evans's Minix 386, and Linux. Then Microsoft Windows 3.1 .