Problems with slow internet or network access on Windows Vista? Try our Vista network troubleshooting and tweaking guide

In our Vista network troubleshooting tutorial, we'll show you how to tweak or change some low-level networking settings in Windows Vista. We only recommend changing these settings if you are having serious problems with your internet or network connection. If possible, test your network equipment on another machine to determine that Windows Vista is the cause of the problem before attempting any of the fixes listed below.

Please exercise caution when following this tutorial!

Although these changes can easily be undone, we recommend trying them one at a time and rebooting after each one. We also recommend creating a system restore point before proceeding. Please note that these commands are for users who are experiencing slow network speeds and not for users who cannot connect to their network/internet connection at all.

To get started, we need to open a Command Prompt window with administrator privileges. To do this, open the Start Menu and search for "Command Prompt". When the Command Prompt icon appears, right click on it and choose "Run as administrator".

A black window will now appear with a blinking cursor. You should now type, or preferably copy and paste any of the commands given below into the black Command Prompt window (right click anywhere in the black window and choose "paste"). Try each command one at a time, rebooting between them if possible and test your networking speeds again. If you are not familiar with copy and paste, see this tutorial.

Ready to start tweaking? Great, we'll go through the tweaking options one by one and say a little bit about what each option does.

TCP Auto Tuning

netsh int tcp set global autotuninglevel=disabled

If this tweak has no noticeable effect on your network performance, we recommend that you turn TCP Auto Tuning back on. There are actually three levels that you can set TCP Auto Tuning to, they are "highlyrestricted", "restricted" and "experimental". To re-enable auto tuning, enter the command below into the Command Prompt:-

netsh int tcp set global autotuninglevel=highlyrestricted

You may also try:-

netsh int tcp set global autotuninglevel=restricted

We do not recommend using the experimental setting however.

ECN Capability

ECN stands for Explicit Congestion Notification. It's a clever new technology that works with your router to improve things when there's a lot of data going back and forth. Unfortunately this technology is incompatible with some routers. To find out if your router works, run the Internet Connectivity Evaluation Tool. If you PC passes the traffic congestion test, you can enable ECN by typing or copying the line below into your Command Prompt:-

netsh interface tcp set global ecncapability=enabled

To disable ECN, enter the following line:-

netsh interface tcp set global ecncapability=disabled

Receive Side Scaling (RSS)

Receive Side Scaling attempts to take advantage of dual and quad core CPU's when transmitting data on the network. This feature is enabled by default. To disable it, copy or type the following line into your Command Prompt:-

netsh int tcp set global rss=disabled

netsh int tcp set global rss=enabled

TCP Chimney Offload

TCP Chimney Offload lets certain network cards carry some of the workload associated with processing network data that would otherwise be done by the computers central processor. To disable this feature, copy or type the following command into your Command Prompt:-

netsh int tcp set global chimney=disabled

netsh int tcp set global chimney=enabled

That is all the tweaking options that we want to discuss for this Vista network troubleshooting guide. Let us know how successful you were at improving your Vista networking performance with these tweaks. You can leave a comment on this article here.