I think the higher the model # you go in retail, the closer the chip will preform like the ES version of the same. Once a series goes into production, it is inevitable that a higher percebtage of slower chips will get binned down just due to volume. During ES prodcution, a smaller amount of silicon is used and quality is held up, so the different parts are going to be closer. I would not be surprised though, to see the retail top end cpu's maxing out in the same neighborhood as the ES's of the same model.