Programming

The 486 was remarkable in that it packed a lot of features onto a single chip, including privilege levels, memory protection, virtual memory, floating-point arithmetic, and a 32-bit address space. These were once features you'd only find in a big-iron machine from IBM or DEC. Even when they did become available in smaller computers, like the Motorola 68000 series, they still tended to require additional chips to implement them, like the Motorola 68851 memory management unit and 68881 floating-point unit. The 486 had all that stuff built in. Motorola was behind, but not by much: they matched the 486's features a year later with the 68040.

Intel wasn't always neck-and-neck Motorola, though. When the 68000 was released in 1979, it was even more revolutionary: it was one of the first 32-bit microprocessors, and very fast for its day. IBM engineers wanted to use that for the IBM PC, but if I recall correctly, management wanted Intel instead because they already had a deal, so they went with the more primitive, 16/20-bit Intel 8088 instead.

And that's a shame. Had they used the 68000, PC DOS would have been 32-bit from the start, and the infamous 640kB limit would never have existed.