Hyper-V Program Manager
Most people who use Virtual PC are running it on a uni-processor computer - and are trying to run other programs at the same time; however, Virtual PC can be very demanding on CPU resources at times. To help people deal with this - we have provided the following performance options under Virtual PC:
A third option is to choose the 'Run Virtual PC at maximum speed' option and then launch Virtual PC using the following command:
Start /low "" "Virtual PC.exe"
This will run Virtual PC at a lower priority than other applications, which will allow it to get all of the CPU resource that is available, while letting other host applications remain responsive. The problem with this option is that it can conflict with other low priority applications like Seti@home.
A final comment on all of this is that as Virtual PC runs all of its virtual machines on one thread - if you have a dual-processor computer - you can just select to 'Run Virtual PC at maximum speed' and not worry about performance as your host applications will run on the other processor.