Virtual PC vs. Power Management

It seems that people are constantly running into problems running Virtual PC on laptop systems with advanced power management.  The reason for this is that Virtual PC is very demanding on hardware and has very strict timing requirements – and as each new revision of laptops comes along these systems perform more and more complex power management.

Problems start happening when these laptops tweak with things that we rely on.  This can either be caused when the laptop changes the CPU frequency too often, or when the laptop actually powers down sections of the system that we are dependant on in order to conserve power.  When this happens the user can see a variety of problems; ranging from sporadic pauses and bursts, virtual machines running too fast or too slow, repeated keystrokes or missing keystrokes to other timing related problems.

If you are seeing these problems you should:

  1. Install the laptop manufacturer’s power management tools.  Sometimes using these to change the power settings can resolve the problem (though not always).

  2. Check for any bios updates available for your laptop.  From time to time we work with laptop manufacturers to address issues we encounter as part of a BIOS update.

  3. If nothing else works – you can almost always solve these problems by installing Seti@home (or folding@home).  These programs use 100% CPU running at idle priority, which means that they do not affect any other programs running on your computer – but they effectively stop the laptop from performing any power management.