Same version here, similar problem. Example page - anything of stackoverflow (like http://stackoverflow.com/questions/1506589/c-sharp-variable-height-for-nodes-in-a-treeview). With internal adblocker disabled, page loads instantly. With adblock enabled, page starts loading, displays content and 3 blocked ads, then page is totally unresponsive for about 10 seconds, then finishes, ads count increases to 4.
Similar problems occur on msdn and many other pages.