I somehow doubt you'd be getting poor frame rate due to the number of entities in the game. All the enemies are 2D images, so the card ain't drawing extra polygons.
I have a decently terrible computer and I don't get much frame loss at all, unless large amounts of entities SPAWN at the same time.Try playing those mega coop maps with tons of monsters in this mod:ÆoD: Aeons of Deathhttp://forum.zdoom.org/viewtopic.php?t=20500And running through every level in wads like Invasion UAC or any other wad with plenty of monsters constantly spawning