HackTrick

Another unnecessary default setting that Vista (and actually XP as well) comes with is a 20% “reserve” of your available bandwidth in order to accommodate certain applications like Windows Update. This tweak is a pretty common one most old-school users of XP already know – it’s not at all detrimental and you can immediately gain 20% of your bandwidth back, increasing Internet performance significantly.

This is called the QoS Reserve Bandwidth Limit, and to reduce this on any version of Vista you need to edit the registry.

Go to Start and type “regedit“. You may have to deal with the UAC, unless you’ve read Sharninder’s advice on how to speed up your Vista by turning it off! In Regedit, navigate to “HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows”



Right-click on Windows and create a new key called “Psched“, then right click on the right and create a new “DWORD” entry. Name it “NonBestEffortLimit” and set the value to zero to disable reserve bandwidth.

This is case where the cutting edge technological advances being enabled on Microsoft’s operating system by default is a recipe for disaster for users who have older networks and older network devices (specifically older routers). Vista comes installed and enabled with something called “Receive Window Auto-Tuning.”

On advanced networks, it’s actually a pretty cool technology where the transfer of data is monitored and Vista automatically “tunes” the TCP window field to optimize packet transfer. Older routers simply do not “play nice” when it comes to that kind of window resizing. This spells trouble for home users who don’t know the difference between a packet of data and a packet of sugar. What was Microsoft thinking?

Luckily – there’s a way for you, the home user, to turn this default feature off as well. First, click on “Start” and type “cmd” and right-click on the command icon. You’ll see the following window.


Click on “Run as Administrator.” Then, in the command box, type “netsh interface tcp set global autotuning=disabled” which will disable autotuning.


Now that you’ve got your new Vista finally communicating with your router (hopefully), you’re ready to tweak Vista even more in order to dramatically boost the Internet speed.