Click Start-->Run-->type "gpedit.msc" without the "

This opens the group policy editor. Then go to:

Local Computer Policy-->Computer Configuration-->Administrative Templates-->Network-->QOS Packet Scheduler-->Limit Reservable Bandwidth

Double click on Limit Reservable bandwidth. It will say it is not configured, but the truth is under the 'Explain' tab :

"By default, the Packet Scheduler limits the system to 20 percent of the bandwidth of a connection, but you can use this setting to override the default."

So the trick is to ENABLE reservable bandwidth, then set it to 2% for XP and 100% for Win7. This will allow the system to reserve at the optimum percentage, rather than the default 20%.
Win7 and XP do not need restart, just click apply.
works on XP Pro, Windows 2000 and Win7
other OS not tested.



tested Win7 7Pure