Jul 04
About 20% of your available bandwidth is reserved by MICROSOFT for their own purposes like Windows Updates and interrogating your PC etc To get it back: Click Start > Run and type “gpedit.msc” without quotes. This opens the group policy editor. Then go to: Local Computer Policy > Computer Configuration > Administrative Templates > Network > QOS Packet Scheduler > Limit Reservable Bandwidth

Here is the original:
Increase Your Internet Speed : A hidden trick!