There is normally a cable between the cd player and the sound card. When running the old C:\WIN98\CDPLAYER.EXE, that cable is required to play a cd. (I'm sure you all knew that.)
However, when a cd is played using "C:\Program Files\Windows Media Player\WMPLAYER.EXE", that cable is not used. (Well, I was shocked.) It appears that the data is read the same as a disk file, processed on the motherboard, and transmitted to the sound card.
You can fix this "problem" by modifying the registry. Basically, change the default HKCR\cdafile\shell and HKCR\AudioCD\shell options.
|CDPLAYER.EXE||1 - 3 %|
|WMPLAYER.EXE without visualizations||1 - 3 %|
|WMPLAYER.EXE with visualizations||30 - 35 %|
When WMPLAYER.EXE was hidden by other windows, its per cent utilization dropped to 3% or less. However, cpu operations, such as saving a file to floppy, produced noticable breaks and skips in the music. As a result, it is my recomendation that WMPLAYER.EXE not be used.