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TinaBelcher

macrumors 65816
Original poster
Jul 23, 2017
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Hi

i plan on ordering 32 go ram from another brand as everyone else cause Apple’s is expensive. But my question is, do I have to remove the 8 gb ram from the iMac , or can I leave it and add the other non-Apple rams? Or will those 2 brands crash and ruin my iMac?
 
You should be fine mixing Apple RAM with 3rd Party as long as the third party ram matches the specification for the system you have. I have just ordered 16GB of RAM from Crucial to add to the 8GB of RAM from Apple in my iMac.

Make sure you order from a reputable website like OWC or Crucial - Both of these have tools that allow you to select your exact Mac system to ensure you get the correct RAM.

Madness in my opinion to get additional RAM from Apple as they just are so much more expensive, unless you have a Mac that can't be upgraded by the user.
 
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I did have issues mixing Crucial Mac ram with Apple's SK Hynix RAM. I'm also not alone on these forms in having some issues with perfect compatibility. You may feel comfortable attributing this to user error on my part, and that's fine, but perhaps consider your return options (or ability to order more of the same) before you order. When I added the Crucial RAM to the two free slots all of the RAM registered, but the speed dropped to 2133. I believe that there is a "work around" making its rounds that you can switch the Apple RAM to either the two lower or the two upper slots and put the new RAM in the other two to bring it back up to 2666, but I believe this drops dual channel. In the end, I just order four sticks of the Crucial RAM and it's all working perfectly.

EDIT: I just assumed that you were talking about the 2020 27-inch iMac, for some reason. If that's not the case, then you should do as most do (wisely) and ignore my comment.
 
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Here's a source that I use:

I notice they don't have RAM listed for the 2020 iMacs yet.
But they should probably know what to use.
 
Funny that i just installed the 2x4GB SK Hynix from 2020 iMac in my 2019 27 inch iMac that i will be giving to the wife as a Xmas present and it just works straight up no issue At full speed. I still haven’t gotten my second batch of OWC ram but hoping that installs in the 2020 without issue.
 
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Thanks for the replies! So, what I want to buy is the crucial brand. However, they don't look identical from one website to another, there's design differences. Yet they are all describes as:
Crucial - DDR4 - 16 GB - SO DIMM 260-PIN - 2666 MHz / PC4-21300 - CL19 - 1.2 V - NON-ECC



This model is taken directly from Crucial's official website, which im gonna purchase from since I live in Europe.
1597575625378.png


Then there's this kind without the extra details on top, and it doesn't have a "M" in the 00XXX0 description. This is the model I'm planning on purchasing, is this ok and safe to buy for the 2020 model?
(weirdly enough, it's cheaper to buy 16 gb twice, rather than a bundle of 2x16 gb)
1597575665271.png



And last there's this weird long kind, which I don't even want to consider cause it looks suspect.
1597575736151.png
 
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I did have issues mixing Crucial Mac ram with Apple's SK Hynix RAM. I'm also not alone on these forms in having some issues with perfect compatibility. You may feel comfortable attributing this to user error on my part, and that's fine, but perhaps consider your return options (or ability to order more of the same) before you order. When I added the Crucial RAM to the two free slots all of the RAM registered, but the speed dropped to 2133. I believe that there is a "work around" making its rounds that you can switch the Apple RAM to either the two lower or the two upper slots and put the new RAM in the other two to bring it back up to 2666, but I believe this drops dual channel. In the end, I just order four sticks of the Crucial RAM and it's all working perfectly.

EDIT: I just assumed that you were talking about the 2020 27-inch iMac, for some reason. If that's not the case, then you should do as most do (wisely) and ignore my comment.
Thanks for the info. I am indeed talking about the new 2020 model. This is the crucial ram im considering. I want to buy a 16 gb twice in a order, since its a bit more expensive if I buy a 2x16 gb bundle

Crucial - DDR4 - 16 GB - SO DIMM 260-PIN - 2666 MHz / PC4-21300 - CL19 - 1.2 V - NON-ECC
1597576466659.png
 
Crucial - DDR4 - 16 GB - SO DIMM 260-PIN - 2666 MHz / PC4-21300 - CL19 - 1.2 V - NON-ECC


Thanks for the info. I am indeed talking about the new 2020 model. This is the crucial ram im considering. I want to buy a 16 gb twice in a order, since its a bit more expensive if I buy a 2x16 gb bundle

Crucial - DDR4 - 16 GB - SO DIMM 260-PIN - 2666 MHz / PC4-21300 - CL19 - 1.2 V - NON-ECC
View attachment 944593
The part number is not explicit. Refer to https://forums.macrumors.com/threads/memory-upgrade-compatibility-list-for-imac-2019-2020.2248911/ for the right part number.
 
If you are mixing different sizes (like 32gb and 4gbs) you need to skip a slot and install in every other as opposed to 32gb/32gb/4gb/4gb. Correct placement from bottom to top is 32/4/32/4 to get the computer to run in dual channel mode. Go to 4:15.
 
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