Chris Beech

Microsoft reserves 20% of your available bandwidth for its own
purposes (suspect for updates and interrogating your machine etc..)
Here’s how to get it back:

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.”

http://www.realtechnews.com/posts/3113