Hi, I have discovered a small program that you can use to "optimize" Windows Media Center. Its a program called FixWin
from The Windows Club. It also comes with so many other fixing tools to optimize Windows Media Player and even fix problems in Windows as well.
I included a screenshot. From what I experienced, it made Windows Media Center reset the TV which should not be too hard to reconfigure anyway but in turn Windows Media Center became more responsive
as mine got a bit lagish overtime. It did not touch anything in my music, picture and video libraries or my FM radio presets anyway.
Plus is free, small and portable that you can actually extract it in your USB and use to other computers. If your WMC feels lagish and if its own "optimizing" module is not doing the job, this should be nice to try.