Few questions: 1) I plan to set the computer up with 3 user accounts running in Fast User Switching mode. Only light usage on each account such as Safari, iTunes, Mail, Messages and then the odd program like iPhoto or Pages. I plan to install 3rd party RAM to cope with the number of open applications but will this usage benefit from the quad core vs dual core. 2) My parents don't upgrade often so I want the machine to last as long as possible - in the future is the HD 4000 likely to become a bottle neck before the dual core processor? What I mean is, there's no point upgrading the processor if the graphics are going to be the bottleneck, right? Thanks in advance!