A friend of mine has an iMac13,2 with 2 x 4GB RAM installed (PC3-12800 1600MHz). I have two 4GB sticks laying around that are PC10600 1333MHz DDR3. Can I pop those two sticks in his last two slots? The RAM I have is from OWC and it says that the OWC1333DDR3S4GB sticks are only compatible with iMac12,2 and iMac11,3. So I know my sticks aren't officially compatible with iMac13,2, but could it work anyway, albeit slower, or not at all?