On Mon, 5 Feb 2018, Michael Kjörling wrote:

Honestly, I think you've got the timeline mixed up. Wikipedia puts the
Xbox introduction in 2001, which sounds about right to me. Designing
the core of the original Windows NT would be about a decade before
that, maybe a little earlier still, around 1990-ish. Around 1990 in
terms of game consoles was the Super Nintendo and Sega Mega Drive
(A.K.A. Sega Genesis), which the original Xbox was definitely _not_
contemporary with. I _think_ (but could certainly be mistaken about
this) that Windows 2000 ("NT 5") was the release that dropped several
non-Intel architectures; I'm _almost_ certain that NT 4 shipped with a
bunch of versions on the same installation CD, and believe that those
included both PowerPC and Alpha.

Pretty sure at least PPC was supported by NT4, but don't quote me.

Also, I think the original NT "personality modules" included OS/2 (but
without Presentation Manager, the OS/2 GUI, so it only supported
text-mode OS/2 applications). The way I recall it, the OS/2 module was
a first-class citizen in NT 3.x, relegated to second-class citizen
status in NT 4.0 (it was there, but you had to jump through some hoops
to get it installed), and dropped with 5.0/2000.

3.51 and 4.0, at least, both had a paid add-on for PM application support.