Well, optimizing your internet settings won't make your connection faster. If you drop cable to go with, say, a slower DSL connection, it's just going to be slower. I don't believe these "internet optimizers" make a discernible different anyway.
But perhaps I misunderstand, perhaps you're talking about internet "accelerators" like some dialup ISPs like NetZero offer. I've used this type of software before from a local ISP on a 56k dialup connection, and here's what I found: it disables some ads, I believe it also disables Flash, it lowers the quality of images in web pages (with a variable quality setting), and uses some sort of cache system. I didn't like it because graphical content is pretty important on the web these days and didn't bring enough of a speed boost to be worth it.