there getting on a bit now(late 2007 i believe). OC'ed you will notice a difference.
I doubt any of the games you would use would ever be able to properly, if at all, utilize the dual xeon cpus. There are not many pieces of software that can and the one that do use them properly are generally advanced 3D modeling programs.
Will play BF4 or Arma 3 most likely, however you would be much better off if you could go i5 and 760.