Dungeon Keeper generally runs very smoothly in DOSBox 0.72, but I found my framerate suddenly hit single digits when I had to possess a dragon in the first bonus level. When you possess creatures (control them with a first-person perspective), several of them have different ways of seeing things; I guess you could call them filter effects. The effect used for the dragon was the first one I noticed that has a severe impact on speed; but after tinkering with a setting in one of the game's tables (CREATURE.TXT) called "Eye Effect" for the various creatures, I found there are others that cause a similar hit in performance. It's easy to get around this slowdown by setting the effect for all creatures to 0 (none), but it's strange that the performance is so greatly degraded by these effects. Has anyone else encountered this?

I tried all the cores (although the game works more smoothly overall with dynamic), all the output methods, no aspect correction, no scaler, no sound, DOS32A instead of DOS4GW, disabled EMS/XMS/UMB; nothing made a real difference. Both original and AI-patch game executables behave the same, and even the game's low-res (320x200) mode gets bogged down with a frameskip of 10. I went on to try some older versions of DOSBox, and although there is still something of a hit compared to using no effect, it is much less severe in 0.65 than in the 0.7x versions.

Please let me know if there is something more I should try; or if there is more information I can provide.