I currently own an Oct 2010 2.13 Core 2 with 4MB of RAM. Im interested in purchasing the July 2011 also with 4MB of RAM. I do quite a bit of web browsing... and watch A LOT of LIVE streaming video. My business is dependent upon that streaming and web browsing at the same time. Im curious as to opinions as to perhaps how big of an upgrade it would be getting the newer model? Anyone have any guesses based on your experiences with both systems? Id appreciate any insight. Thank you in advance.