Interesting, I think I've encountered similar lag before, on Avernum 4, Of course, that was just before my older system seemed to DIE..., RIP old Computer.... In any case, I think I'll be checking Avernum 4 again soon. Good luck to all..
P.S. I don't recall my computer crashing on Avernum 4 though. It was sometimes lagged though. Hopefully, my newest computer is immune to any lagged effects. I will check soon.
Seems, okay for now, I just ran through some of the first goblin dungeon without any performance issues, it might be slightly slow during an autosave, but I currently have Antivirus software active and I have a AMD Athlon 64 X2 CPU at 3Ghz per core.. and 2Gbytes of RAM, and a GeForce 8500 GT by XFX, and Running Windows XP 32-bit. Oops, guess I overdid my explanation a bit... I wish everyone good luck. Bye for now.