I have a 2.4 GHz i5 15" MacBook Pro 2010. I have been searching alot on both google and in the MacRumors Forums, but I have been unable to find a solid answer. I currently have 4GB with RAM, but I'm going to upgrade to 8GB and I'm wondering if 1333mhz RAM will work or not. Reasons, if it runs at 1333mhz, I will have a slight, only slight, boost in performance. If it downclocks it to 1066mhz, I still have 8GB of 1333mhz RAM that I can put in a new MacBook Pro, if I decide to buy one in near future, and the 1333mhz RAM is slightly cheaper. It's not a problem to buy 1066mhz, but I would prefer 1333mhz if it works. Has anyone tried this?