Is there any known issues with UDP performance on Winodws XP? We have an application which downloads data from two sources, one of which uses UDP, the other TCP. The TCP portion of the download works fine but the portion downloaded via UDP slows down and eventually fails. I've been looking into QOS settings since this is related to streaming voice, but they have not worked. I've also attempted adjusting window sizes etc as per speedguide.net, but as those are specific to TCP, I do not expect them to make a difference.
 
The TCP/UDP sources are located several hundred miles from us, and we are connected to them via two T1s. At first we thought maybe it was a network issue, but we've tried pulling the same data with NT machines and have had no problems. Any help would be greatly appreciated.