Game is choppy to the point of unplayable, have tried adjusting resolution and graphical settings to no effect. I'm using Windows 8.1 and have an NVIDIA card.

That has pretty much fixed the issue. Thank you good sir!!

no problemo

I don't mean to be rude, but you should indicate that the question was answered.

Not rude at all, I had forgotten to mark the solution. Thank you for spotting.

You're welcome.

Forcing off vsync in the Nvidia control panel sadly didn't take care of the issue for me but luckily I found that you can also turn it off in the game's configuration file (which is a more elegant solution anyway).

Go to the "System" folder in the game's directory and open the file MenofValor.ini there. Go to the line that says "UseVSync" and replace "true" with "false". That fixed all performance issues for me.