I have the same issue. It started when the merge happened between MT, Open Beta and Stable. It got worse with the second update.
I've tried everything I come across - resetting the 0 and 1 cores, limiting my fps to 60 to match my Trackir, reducing my graphics and others that I've forgotten already.
I haven't tested the Caucuses map yet. I'll be pleasantly surprised if the stutter is actually gone, but I'm expecting it isn't.
Maybe opening a ticket that INCLUDES THE LOG FILE is the only way to go....
EDIT: The Caucuses map has NO STUTTER! Yay. I guess I'll play that for a while.
I am pleasantly surprised!