Correct and reliable Mac RAM can be purchased from online Mac RAM sources Crucial memory or OWC (macsales.com).
OWC thoroughly tests all the Mac RAM they sell for Mac compatibility.
Macs are seriously picky about RAM.
IF the clock speed is off, the amount of pins is wrong or the RAM's timing latency is not within Apple's spec, the RAM you are purchasing may not work or give you issues in the future if it does.
OWC ships to Canada.
IF the RAM you purchase from your source gives you any issues and doesn't work in your iMac, OWC will have the exact and correct spec'd RAM for your year and model Mac.
They have a lifetime free replacement guarantee on all of their Mac RAM if any RAM modules fails prematurely.
There are only 2-3 sources of Mac compatble RAM!
Macs can't just use any wildly nilly RAM that are usually used in Windows PCs.
Yeah, OWC is great, but Canadians have to deal with longer shipping and customs hassles and charges. Not ideal.
What I don't get is that when a non Mac stick of RAM has the exact same specs as RAM that is Mac tested and approved, I wonder what the actual difference is that makes it incompatible. Here's the Corsair RAM that I sent back: http://www.corsair.com/en/memory-by-product-family/mac-memory-upgrades/corsair-m ac-memory-16gb-dual-channel-ddr3l-sodimm-memory-kit-cmsa16gx3m2a1600c11.html
So what is different, spec wise, than Crucial or OWC that makes it incompatible? Is it some secret ingredient, like Kentucky Fried Chicken?
Here's the specs of the RAM from Corsair
Memory ConfigurationDual Channel
Package - Memory Pin204
Package - Memory FormatSODIMM
Speed RatingPC3-12800 (1600MHz)
Here's OWC's Specs for their RAM for your iMac year and model.
The non-ECC and non-parity items are usually the specs that seperate good, functioning RAM from RAM that doesn't have either one of these as part of the specs.
That's based on my own personal experiences with RAM compatibilty over the years.
It, also, maybe the 8-layer, low noise printed circuit board, itself, as another feature of proper Mac RAM.
Right, so your thinking is that the absense of those specs is a sign that they may not match. I get that. Also, I tried to contact Corsair for support and they have no phone number and have not replied to my email from last week yet, so really, not much in support. I will avoid this company in the future for all these reasons.
Thanks for your help.