A real DOS machine is running on a 8086 (or 8088)
ISA is part of IBM-compatibility.
I did testing on a K6-2 300Mhz, and yes it has 2 ISA slot, one of which is where I put the Sound Blaster 16.
Compiling an SDL port of Quake quake gives you 90% performance at 320x200 and 97% at 640x480 compared to the original. That's about 45fps which isn't bad I think.
SDL3 should now work with any i386+ with a VGA and 4MB of RAM which is roughly the requirements of Doom.
Define "real DOS machine".
But I would give you my definition: something with ISA slot so you can hear that awful 2.0 stereo SB Pro-compatible with a hiss what could be almost parseltongue. Video card of choice.
So basically anything between 386sx to P3 Tualatin and some rare and weird cases even P4 and AMD Athlon.
https://theretroweb.com/motherboards?page=1&itemsPerPage=24&...