That's strange . My sql server DB performance improved a lot after moving our high OLTP site to Sql Server 2012 recently. Same HP blade type with identical CPU and memory. Only difference I can think of is that we have Window Server 2012 on new machines. Not sure if that may have any performance impact but certainly it should not degrade as in your case. I would keep following this thread as there is lot of good information in here and we have more db's being moved to Sql Server 2012 this year.
Discussion on question by prog_sr08: …
Discussion on question by prog_sr08: …