For comparison, the minimum amount of RAM required by the precursor of Mac OS, NeXT, - 32MB (that's megabytes) - seemed insane. But then again, 90% of the computer science - including experiments in AI - had been done (at least, up until mid-80s) on computers that had less than 1 megabyte of RAM. (IIRC, the first version of UNIX was designed to run on a computer with 24 kilobytes of RAM.)