Xeon is WAY better. Not only is it noticeably more powerful, it also consumers more than 2x less power.
Grab the Xeon. It's better.
Also, if you are on LOW budget, you can get this sytem and upgrade it:http://www.ebay.com/itm/Dell-Precision-T3500-Xeon-Quad-Core-X5570-2-93GHz-8GB-RAM-500GB-NVIDIA-/171964581081?hash=item2809e344d9:g:KXQAAOSwT6pVt9Ru