I had the same problem on my new rig.
Two things that completely made this go away for me are:
Disable "Load Textures on Demand" and "Force Single Threading" in the Warband launcher, first one in the Video settings, second on in the Advanced tab.
Lots of people reported improvements with Multi Threading enabled but i am running one of those i7-2600k Sandybridge CPUs and that had problems and caused freezes for me.
Just give it a shot.
Also in case you run into screen tearing due to VSync being disabled (which i would recommend) set your FPS limit to something that is not a multiple of your monitor refresh rate.
I just put it to 999 and never get any screen tearing.