DrTcp.

[maxping]

If you want a simple way to tweak your RWIN & MTU have a look here -

http://www.dslreports.com/faq/578

I use RWIN (tcp receive window) 200480 & MTU 1500.

Make sure your have your Network Interface Card or modem in the Adaptor settings drop down, after  applying the settings reboot the pc for the settings to be saved.

[Rik]

A tool I prefer for the job, Max, is TCP Optimizer, available here. Once settings have been changed, use TCP Analyzer on the same site. There's also a speedtest there. Overall, I've found the results more useful from this site than DSL Reports, but it does no harm to check both out. I'd also recommend Netmonitor tweak test.