Speed Tweaks

A lot has been written about how you can tweak your Windows registry to improve the performance of your TCP/IP connection on a Cable Modem or xDSL modem. If you cut all this down to the bare bones, what you benefit from is really quite limited (but it does work). The following is a quick guide, aimed at Windows 95/98/Me/2000/XP and NT users. Linux and Mac users need not do anything.

Step 1 - Test your current speed

This is essential, so you have some hard data to compare before and after. Do not just assume that you can "feel" the difference. You may be able to do that, but it is just too easy to forget the before-"feel".

The best way to test the speed is to do a pure FTP download from a server located at the CMTS head-end. By using a server at the head-end, the test will hopefully not be depending on too many internet bottlenecks. You will need to find a suitable server and a good big file. Also make sure you are not being tricked by some caching along the way – download the file a couple of times and compare the download times.

Step 2 - Windows 98 Second Edition Only

If you use the Second Edition of Windows 98, and you are using the ICS (Internet Connection Sharing) feature, then this article in the Microsoft Support Knowledge Base is a must-read: "Q230116: Slow Transfer Rates with ICS and High-Bandwidth Devices".

Step 3 - Backup the registry

Use Start Menu>Run... and type REGEDIT to invoke the registry editor. Use Registry>Export Registry File... to backup the registry. Make sure you have All selected in the Export range box.

Step 4 - Tweak the registry

Windows 95/98/Me

Download and run to change the TCP Receive Window setting to 32767.

Windows NT

Download and run to change the TCP Receive Window setting to 32767.

Windows 2000/XP

Download and run to change the TCP Receive Window setting to 32767.

Windows 2000/XP note: The TCP/IP stack in 2000/XP automatically adjusts the setting, if you don't specify something. So while this tweak will not hurt anything, it will disable this automatic adaption to the line latency. In other words: don't expect wonders with this tweak on 2000/XP.

Step 5 - Test your new speed

Use the same method as in step 1, and use this as a verification of the installation. If you got a significant improvement in the speed, then great! If the speed is the same, then don’t worry. Nothing is broken. If the speed is lower now, then you should consider undoing the tweaks by importing the backup copy made during step 3. This will however, most likely not be the case.

Note that you should try to do the test under similar load conditions, i.e. same time of the day etc. Again make sure you are not being tricked by some caching along the way – download the file a couple of times and compare the download times.

Total Speed Freak?

Chris over at www.HomeNetHelp.com posted a quite interesting article on ganging multiple IP connections together over a single cable modem in order to increase throughput. If you are a total speed freak, you should check this out.