I am not 100% sure how this service works, but, it is trusted.
http://www.dslreports.com/tweaksIt has information and tools about how to adjust your TCIP settings to get them optimized to your connection.
Windows Vista is already as optimized as it can get in this department, if you happen to be running it, you may be out of luck.
Also, using tools like AdBlockPlus in FireFox may help with speed issues, as ads often take a longer amount of time to open.