Been lurking for a good few months since deciding i wanted an iMac back in March (i guess everyone has been) and thought i'd finally get involved in the forum! Quick question - first of many no doubt. Is the performance boost of the CPU's in the title substantially different? I know it's for the current iMacs but it's a good guess that the spec jumps will be of an equivalent (relative) amount with the new iMacs. Seems £160 is a little steep for a 0.1GHz increase, guessing it's the i5/i7 change that is the difference. Would it be a blatantly noticeable upgrade? Is it worth it? Would i be better off investing £160 in upgrading RAM instead? Also, does replacing the RAM void the warranty (assuming the new RAM isn't soldered)? Been slugging away on my Macbook Polycarbonate since 2008.. it can't handle Xcode, Firefox, Skype and Photoshop at once anymore.. really can't wait to get a decent machine. Hopefully in 34 hours time this forum will be buzzing with excitement!