I use twonkymediaserver 5.1.4 (works best on my server machine) to serve audio to Windows Media Player 11 clients on MS Windows Vista. This works great, but I've noticed the a peculiarity:
\%UserProfile%\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5 keeps growing in size over time. This is the location where WMP11 seems to keep its disk cache size for the streamed UPNP data in MS Windows Vista. After a couple of weeks/months of using WMP11 as upnp player, this location can easily grow into the gigabyte size range.
Is this a problem only connected to TMS, or inherent to how WMP11 works? I don't have another upnp server to compare with unfortunately.