wmpnetwk.exe throttling network speed on xp pro server

hey all, I've noticed a very strange behavour that is similar to the vista media player throttling issue where the implementation of the media server function slows network throughput to less that 15% total capacity. In the vista case that is caused by an over QOS type function that invokes a service called MMCSS. that issues is described here:
http://blogs.technet.com/markrussi [...] 33290.aspx

Unfortunately I can demonstrate the exact same behaviour when wmpnetwk.exe is active on the server. if I shut it down manually and restart a file transfer I'll see speeds at the rates I expect. when it comes back on, the rate drop to 150 mbits per second on my gig E network.

any ideas? I need to run the media sharing as I use it to stream content to my ps3...