I only have the GOG version...
How does the GOG version run? ..& what OS are you using to test?
i remember running it recently and it would crash. odly, just having 1 core enabled was the fix. so it has some bugs but i believe there is a fix. as far as fps is concerned, no trouble at all.
So it's a single core/thread game. I will give it a go on dual core, currently downloading (GOG version)