Although virtualization technologies have been a great help to data center managers looking to reclaim power in an overburdened environment, virtualization can also create problems. As IT organizations complete their server virtualization initiatives and as their virtualization management skills mature, use of the physical server power management features and dynamic workload shifting capabilities will increase. This, coupled with increased adoption of server hosted desktop virtualization, will create new opportunities for improving the efficiency of data center power and cooling systems, as well as new challenges for keeping up with increasing demand.