To this I would like to add a couple of more relevant links off of my home page. First of all Code Complete has a sample chapter online on Optimization that is worth reading. Secondly those who want to get into great depth on how to design web-servers and network protocols for maximum performance may find many things of interest in The C10K Problem. Another good reference is this rant on Latency vs bandwidth. Many slow applications are slow because of heavy duty interactions across something with bad latency, and not because of lack of bandwidth.