Updated: May 8, 2010
First, let me start by saying that I do not believe in system tweaking at home. Most people do that as a sort of a compulsive hobby, without really knowing the consequences of their actions. At home, there is little reason to change the system configurations.
However, sometimes, just sometimes, your operating system may be in a need of a little greasing up to get going properly. In these extremely rare cases, where you're facing a fully reproducible problem that is not caused by any external or environmental changes, you may want to try some small fixes. Today, I'd like to talk about network optimization on Windows.
Before you start ...
A few words of friendly warning:
Do not tamper with your system if you don't fully understand the implications of each and every change. And when you do, make one change at a time and monitor the behavior closely.
Make sure you have a valid backup, preferably a complete system image - or at the very least, manual backups of your data and registry, and possibly System Restore. Make sure your problem does not manifest in hardware, otherwise you will never really know what the source of the problem is. You need a stable environment to make changes.
This is where you go when the Internet ghosts are misbehaving.
A friend recommended this site as his first 911 station for troubleshooting network problem. Since he has far more experience than me in running 24/7 full-throttle up and down the broadband wire, I hopped by the site for a first impression.
Quoting the website mission, SpeedGuide.net focuses on system performance, with areas including Broadband Internet connections, Windows, Overclocking, all targeted towards a technically aware audience. A large section of SpeedGuide.net is dedicated to Cable Modems and DSL technology, stressing on improving TCP/IP performance over high speed/latency networks. There you go. Now, let's examine a couple of tools that the site offers.
This online tool can perform the first initial, basic profiling of your network connection. Sub-optimized parameters, like MTU and MSS will be listed.
If this is not good enough for you, then you may want to try TCPOptimizer.
TCPOptimizer allows you to change a range of parameters in the TCP/IP stack, first by performing a series of basic checks to determine optimal settings. For instance, TCPOptimizer can determine the largest non-fragmented size of a packet you can send over your network. Then, it can also provide latency test results.
Based on these findings, you can tweak your setup. You can go for optimal, program-suggested values or input your own. And best of all, the program allows you to backup registry before making changes, so you can easily revert if something goes badly wrong.
After making changes, reboot and then observe closely. Make sure you perform a wide range of tests to ensure the fixes are positive, including download/upload tests, instant messaging, VoIP, ping latency, and more. If things don't work out, revert to backup and back to square one.
Don't expect magic at the end of this article, because there isn't any. Be very, very careful about changing your system. Use tweaks as the last resort. But if and when you do, make sure you use the right tools for the job.
Network wise on Windows, TCPAnalyzer and TCPOptimizer should serve you well. Unfortunately, I can't provide you with any concrete examples, because specific settings are only valid for the particular user, computer and infrastructure at hand.
As you may have noticed, I've purposefully omitted giving you pinpoint advice. Optimization is concept as much as black art. Make sure you do not concoct a potion you would not want to drink yourself.
By practicing sane computing, and some help with useful programs like Secunia Personal Software Inspector (PSI), TCPAnalyzer, TCPOptimizer, PC-Decrapifier, and a handful of other worthy programs, including a range of former Sysinternals tools, you will manage to have your systems perform at the peak of their ability.
For more details about great, must-have Windows software, please consider reading my recent cool apps mega collection. Likewise, if you have generic, golden-rule suggestions about network configurations on Windows, feel free to contact me. Remember, not your personal hacks, but proven tips and tricks that can benefit everyone!
Many thanks to Mr. A.W. for this suggestion.