The world is going virtual and even we love to run SQL on Actual hardware, we can not stop it. There are so many factors which is driving virtualization.

I would recommend that you read through it.

http://www.brentozar.com/sql/virtualization-best-practices/

Also try to identify where the issue is.. it is not sql server 2008, that I know. SO look for other issues like resource contention, stale stats etc...