No its not a Sprint issue. As I said, I can tether with linux (using the usb-rndis-lite part of SynCE) and its completely stable. So stable in fact that my speed is over 4 times what I get with a USB tether in Windows...
The problem lies somewhere in Vista or WMDC... I just can't figure out what the issue is.
:::.. Download Stats ..:::
Download Connection is:: 1965 Kbps about 2 Mbps (tested with 25598 kB)
Download Speed is:: 240 kB/s
Tested From::
http://testmy.net/ (Main)
Test Time:: 2008/05/24 - 11:48am
Bottom Line:: 34X faster than 56K 1MB Download in 4.27 sec
Tested from a 25598 kB file and took 106.722 seconds to complete
Download Diagnosis:: May need help : running at only 46.27 % of your hosts average (spcsdns.net)
D-Validation Link::
http://testmy.net/stats/id-Z15JKITRF
User Agent:: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9b5) Gecko/2008050509 Firefox/3.0b5 [!]