Hi, I am going to order a new iMac and am struggling to decide on whether its worth it to go for the M395 or just stick with the M390? Looking to see if anyone has any idea if there is much of a performance difference? Will be used as a second machine just for general computing (email, web, iTunes, iBooks, iPhoto etc) no gaming or anything too serious. Planned configuration is 27-inch, i7, 256 Flash drive. Looking for about 4-5 years use. Thanks for the advice.