I'm trying to upgrade my 2012 iMac memory from 8GB to 16GB, like most I'm trying to find reasonably priced memory. From my previous Mac mini experience I've known for some time that there is no "Apple memory", Apple does not make memory, they buy it from many vendors...its just memory. However, you get the wrong one and your iMac starts acting goofy or not boot at all. I've searched and there are lot of advice; - Apple doesn't make memory - Anything will work, just make sure specs are the same - Go to some memory makers site and do a search - Apple memory costs more because it has "special" memory specs not listed on the general public specs (this may be true, but feels a little snake oil'ish) - skepticism over lower priced generic "Hynix" memory, turns out it is one of the brands Apple uses What I've been looking for is; "I've tried memory x and it works". What I found on sites like Crucial are Apple and generic PC memory that list the same specs. The only difference I could note was Apple memory is Mercury free and one other nasty chemical I can't recall. Basic memory spec are DDR3L 12800 1600mhz SODIMM 204 pin, the "L" is low power, 1.35volt vs. 15volt. Where things get harry is in memory timings, CAS timing, etc...The first number I see on the label "11" should be the key memory timing of CAS 11 or CL11. Not an expert, please correct me if misstating. There are host of other timings that define a module and reason a given memory module part number could have unique suffix. So, my iMac is late-2012 i7 3.4GHz with factory 8GB memory. I've attached a picture of the memory as it came out of my iMac. - Hynix memory. - 4GB 2Rx8 PC3-12800S-11-12-F3 - Part Number HMT351S6CFR8C-PB NA AA (not sure what NA AA is, I don't think it matters) - The label has the "eco" logo, this may mean low power (L) - Made in China Memory I've tried so far is a Samsung brand that came out of my HP Elitebook, same specs as above, CL11 timing, but rest of the timing notations do not match. There are also fewer chips on the module. This may have something to do with R1x8 vs 2Rx8 on the Mac memory. This Memory WORKS, passed the hardware memory check (the short version). - Samsung Memory - 4GB 1Rx8 PC3L-12800S-11-13-B4 - Part Number M471B5173DB0-YK0 - Made in Philippines If you have other memory that has worked, please post.