Intel has posted an article that specifically addresses code optimization. From the article, "optimization is not a form of black magic, but a regular part of software development. If you use a methodical approach, such as the closed loop, and work your way sequentially down to lower and more subtle levels of optimization, chances are good you will gain most of the performance advantage your code and the system can deliver. To do this, you will have to take careful measurements, experiment, verify, and iteratively repeat the process at every layer of attack. Tools should be chosen and used with the same exacting care as the methodology is applied. Between good tools and good process, you will definitely produce faster and better code, as well as happier and more satisfied clients and customers."