All of the RAM manufacturers are already selling RAM for late 2015 iMacs except for Crucial. After some digging it appears as if Crucial has two tiers of RAM: 'Generic' and 'Premium' They already supply the 'Generic' RAM for late 2015 iMac, although its not officially listed on their site as late 2015 iMac RAM. As someone who has no idea about RAM, but wants to buy some for my iMac, i'm just wondering if its worth waiting for the 'Premium' RAM which they say will be available in the next few weeks? What will be the difference, if any, to RAM already available?.....One set i have my eye on are the Kingston Hyper-X. Should i buy these or wait?