Unreal was such a beast back in the day that it completes beats Quake 2 and other contemporary FPS even on software rendering. TBH it still looks beautiful even by today's standards, if you ignore the low polygon counts.
I'm not a person who cares too much about graphics, even for FPS (I don't really enjoy most of the modern FPS except Wolfenstein, which has interesting gameplay), and I argue that too much graphics eye candies simply decrease the overall quality of the game, but 3dfx definitely was a huge bang back in the day.