title: .Net 3.5 Dll's in a .Net 4.0 application any issues
body: <p>We are planning to move a legacy application which uses enterprise library 4.1 which uses .Net 3.5 in a .Net 4.0 web application.</p>
  
  <p>We are wondering will this cause any performance problems? Will the .net 3.5 code run in a different
   application pool?</p>