BIG NEWS !
Switched the game to CORE 2 only and stutters are almost gone.
When I stay in in one place - no stutters, when moving very slowly slight stutters but that migh be more fps problem I am not sure yet.
When moving normal speed NO stutters.
So it really moight be multiple core thing in the end. Hope this helps
UPDATE: For some strange reason the game now runs without stuttering even on both cores. Here are other things I have done:
Defragmented hdd where game is installed
Stopped windows from creating itīs own virtual memory file and assigned space for it /because I have no idea how this works I assigned 7000MB on both disc C and D. PLayed the game about3 times since then - first two times stuterred , third time /when I switched one of the cores off - no stutter, which so far has been the case/.