Many included "better" features that depended on a somehow non-compatible BIOS. Quite a few of those had dual modes so you could get PC compatible but slower or

Many included "better" features that depended on a somehow non-compatible BIOS. Quite a few of those had dual modes so you could get PC compatible but slower or worse, or incompatible but better. They eventually died out. One company I remember that was pretty successful for a while were Apricot: https://en.wikipedia.org/wiki/Apricot_PC https://en.wikipedia.org/wiki/Apricot_PC