Agree with the day to day usage comment. If you do tasks that really involve memory then the slower stuff you might "feel". General rule of thumb is each CL timing is worth one speed bump. So CL8 1333 would provide similar results as CL9 1600. If this is a general use and gaming machine then I'd get whatever cheap and reliable set you feel comfortable buying. If you'll be doing picture or video editing and need the speed, faster and lower time ram is for you.