Windows XP reserves 20 percent of the Internet bandwidth for QoS ( Quality of Service). This is unnecessary and can be disabled. By disabling this you get a boost in the Bandwidth. Follow the following steps:
* Select Start > Run and enter gpedit.msc to Open the Group Ploicy Editor.
* In the left-hand column in the window, navigate to Computer Configuration > Administrative Templates > Network > QoS Packet Scheduler
* In the right column double-**** on Limit reservable bandwidth and select Enabled.
* Change the Bandwidth Limit to 0 and **** OK.
Now you've disabled the QoS and enjoy the extra bandwidth.