A 486/66 ran Doom well and Duke Nukem 3D mostly ok. (Even a 386 run Doom, although quite poorly.) It's quite reasonable to be able to draw a few polygons on it

A 486/66 ran Doom well and Duke Nukem 3D mostly ok. (Even a 386 run Doom, although quite poorly.) It's quite reasonable to be able to draw a few polygons on it at low res, although it can depend on tricks and skill of the programmer - including math approx yielding a visually good enough result for a fraction of the computing power required for the exact one - to get very good or mediocre results.