DRTCP

DRTCP screenshots

DrTCP is a small utility that stores adjustable TCP settings
Main window
DRTCP 0.2 : Main window

Alternative downloads

Tweak UI
2.10
FREE
PowerToy that allows you to customize many hidden options.
TCP Optimizer
2.0.3
FREE
SG TCP Optimizer allows you to tune and optimize TCP and IP related parameters.
Tweak N' Tune
1.1.0.119
FREE
It is a windows tweaking utility to modify Windows internal settings.