I seem to to having similar problems, but my outlook will freeze for like 3-5 secs then respond for the same time then freeze again, so on and son on .
Very annoying as u go to click on something and its frozen, then its not, OMG!!
I am runing windows 7 ultimate 64bit and outlook 2010.
Found the problem for me :)
It was the Trend micro toolbar in the ADD-ONS of outlook .
There must be some compatability issue there somewhere, since i have disabled it it runs smooth as now with no freezing.
Hope this helps,