I just found an excellent tutorial on Scott Kelby's Photoshop Insider.
My Lightroom has been running horribly. I was down to a mere 2GB of hard drive space and could barely get any editing done without dragging, dropping, deleting...well, I'll save you all the gory details but believe me things were not pretty in the Thalman home.
I am so happy I found these optimization details and I have cleared up my Lightroom Catalog significantly and my Pro is working like once again....
Check out Scott's article HERE.