My HP pavilion xf255 came factory installed with Windows XP and some software. To playback DVDs there ist the Intervideo DVD player. Whenever I played a DVD, my computer would regress into long bouts of disk access and audio stuttering. Booting was taking forever. In short, the laptop was unusable. And I blamed the laptop.
I also have Linux Mandrake 9.0 installed on the very same laptop, and appart from other shortcomings, the machine performed just fine, so I knew it wasn't anything hardware related.
One thing I noticed under Windows XP was, that disk activity was slowing down my computer. This was especially apparent during audio playback. I know that my chipset supports DMA (Direct Memory Access), so I looked at the Advanced Driver Settings of my harddisk and discovered that it was not in DMA mode, and couldn't be put into DMA mode either.
According to the discussion I had to change a certain value in the registry that controls what transfer modes a particular device can have.