Wow. So I tried to play Chasm again and it still runs quite slow in 640x480 mode. I posted that on Arstechinca, and when you type "chasm rift boxer" in Google this thread is listed first in the results. Yes I incorrectly called it The Dark Rift 😀
I use Boxer on hackintosh with an E8400 3ghz, 8gb ram ,so I don't think my "shitty mac" has much to do Chasm running poorly. It runs much better at 320x240, but I want to use the hires mode. Carmageddon too runs very slow in Hires, as does Skynet (when it works).
Perhaps its Boxer problem, but since Boxer is a frontend for DosBox maybe is a Dosbox OS X issue? I use Boxer because no other frontend is nearly as slick or as easy to use.
I'll try messing about with Dosbox under W7 to see if Chasm runs as poorly under hires.
For those who are saying it runs "fine" for them are you saying it runs smooth (i.e. playable say 30fps or more, any less and its not worth it imo), or that it just works. Of course it works, just runs slowly under 640x480 mode.