The server looks great!.  UT3 drives its CPU at an avg of about 40%, is taking less than 400MB Ram, and the system paging rate is low.  Bandwidth util is low.  A good indicator that the system is running fine is that you've set the page file to max at about 8GB but it's only using a 2GB page file.

I looked at this after I started running into some jerkiness in game.  My ping was 70 or so so it probably wasn't network related.

Have you set processor affinity for UT3?  It runs 9 threads and it looks as though they may all be running on one proc.  Just curious.