The TCP Optimizer is a free, easy Windows program that provides an intuitive interface for tuning and optimizing your Internet connection. Just download and run, there is no installaion required.
The program makes it easy to find the best MTU and RWIN values, test latency and tweak all the important broadband related registry parameters. The Optimizer can be helpful with tuning any Internet connection type, from dialup to Gigabit+
SpeedGuide
SpeedGuide