CPU and Browsing Effect

Does anyone know of a good site or paper that can give me information as to the effect of CPU speed on Internet Browsing?? I am under the impression that the difference in CPU speed will have minimal effect in comparison to things such as connection speed, browser type/version, and data set being retrieved. Is this a false assumption? More specifically, will I see a noticeable difference between a 400Mhz machine and a 600Mhz or 800Mhz machine?