im guessing you mean

"""""""" I talked about this to a friend of mine who's a Microsoft engineer. His response:

(...)
this is because media player is the only app known today that uses the MMCSS stuff
it elevates the priority of threads in a process registered with MMSCS to the realtime level which cannot be done by an app itself
only the MMCSS (a system component) can do that magic
it's a bug because obviously that leaked to WoW
it will starve the crap out of anything running in the background

http://msdn2.microsoft.com/en-us/library/ms684247.aspx

***

Translation: Your computer usually reserves a certain % of the CPU for background applications. Having WMP opened changes this behavior and allocates all available CPU to WoW. Little to no CPU time will be given to background applications and services, therefore increasing WoW performance.""""""""""""""""""


its a load of BS as i run 5-7 applications open at a single time and none of them lag with wmp open ( of course i always have music on).

wmp is also always minimzed into the little fast forward and play buttons.