I have a late 2013 Imac with 2 modules of 4 GB RAM each. In order to max out its RAM capacity of 32GB, I should add 24GB of RAM. This means 12GB each slot, as only 2 slots are free (4 in total). Are there any modules of 12GB memory even available? It seems the multiplier is 4, 8 or 16GB. My other question is: can you recommend a good US online store and brand to buy these? Here are the specs of my Imac: Model Name: iMac Model Identifier: iMac14,2 Processor Name: Intel Core i5 Processor Speed: 3.4 GHz Number of Processors: 1 Total Number of Cores: 4 L2 Cache (per Core): 256 KB L3 Cache: 6 MB Memory: 8 GB Thanx in advance.