Stay away from this tweakThese settings violate the HTTP protocol, and give you a speed boost by flooding the web server with 20-something connections for every single image and page request. There's a reason that they're not the default.
These settings will not only cause many web servers to have problems, but they can also make your web browser be mistaken for a flood attack, which will make the server add your IP to an "ignore" list. Stay away from these "optimized" settings, unless you know exactly what they do and how they work.