Hyper-V’s primary target is servers. We love it when you run it on your desktop however you might encounter some challenges. One such challenge is that once Hyper-V is installed on your desktop box you might find the overall system performance has dropped.
The most common problem users are experience is related to hi-end graphics cards and drivers. In Windows Vista / Server 2008 we switched from our XP driver model (XDDM) to a new more performant model (WDDM). The new drivers used non-cached and write-combined memory in order to allow graphics cards to pump lots of data around the system without impact on CPU caches. This improves overall system performance.
The new model works great on non-virtualized hardware. On virtual machines the model causes lots of root TLB flushing (Virtual to Physical address translation cache). It is this constant flushing of the root’s TLB that is slowing down the system.
There are a couple of things you can do today;
For addition information on the issue see http://support.microsoft.com/kb/961661