I have a 2012 iMac 27" and also a MBP Mid 2009. I want to upgrade RAM on both and have a plan, so wanted to check if it would work. I would buy 2 x 8GB 12800 for the iMac, which will replace 2 x 4GB 12800. Will the 2 x 4GB 12800 go into the MBP when it is rated for 8500? I have read conflicting stories, I'm interested in whether it will work and also if there is any performance implication (I understand it would only run at 8500). Thanks!