Hi guys, I wonder if you can help me. I want to buy a new 27" iMac (probably retina) but after reading the buyers guide I am a little confused as to what has been speed bumped and when. I read that the 21.5" is expected to get an update in an October event but no mention of the 27" or 27" retina. If someone could explain exactly what was updated when and if it is prudent to buy a 27" retina now or wait I would be really grateful. I don't want to wait another 2 months for the October event if I may as well just buy it now. Also, do the 21.5" & 27" iMacs still allow you to upgrade your ram or have they stopped that now? Many thanks!