I want to buy entry level 15" Macbook pro with retina screen. It will mainly be used for internet browsing and playing strategy games such as Civilization V and Victoria 2. No video editing. Will I see any significant performance improvement on getting the newly upgraded 2.4ghz as I maybe able to get a 2.3ghz model slightly cheaper? Screen and graphics are much more important to me than battery life. Many thanks for any advise.