Testing 101: By- MutantKiller
A few commandline tests to checkout how your server is preforming.

Bandwidth Speed Test - This site will tell you your Bandwidth speed for your Cable / DSL modem...https://www.speakeasy.net/speedtest/
Use this before and after you apply any Registry tweaks so you can compare the results of the tweaks.

Cable / DSL Modem Tweaks - This site has all kinds of information on modems and Windows for Cable and DSL. It is a must http://www.speedguide.net.

Testing your ISP connection: By-QAPete
Don't just test your Server, test your Internet Service Provider too!

Tweaking Your Unreal Server: By- 1KrazyFool
Some tips on how to reduce Memory usage and setting up a Server.

Unreal Tweaking Tips: By- Various Authors
Misc tips for tweaking your Server.

Configuring Your .ini: By- MutantKiller
Setting up your Server's ini for better performance.