Broadband internet users can significantly speed up downloads. As it turns out, Windows XP Professional (which this tweak requires, by the way) allocates only 20 percent of the available bandwidth to your internet connection. By opening gpedit.msc --->Computer Configuration ---> Administrative Templates ---> Network---> QoS Packet Scheduler and setting the Limit Reservable Bandwidth setting to "enabled" and the limit to "0%," you can squeeze additional download speed from your connection.
edit: gpedit.msc can be accesed by going to start--->run-->enter gpedit.msc---> click ok
gpedit.msc =Group Policy Editor
It is a tool exclusive to Microsoft Windows XP PRO