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Memory upgrade compatibility list for iMac 2019-2020

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The first post of this thread is a WikiPost and can be edited by anyone with the appropiate permissions. Your edits will be public.
Soulflower

Soulflower

macrumors regular
Jul 17, 2011
185
29
This is a different listing that the original one in this thread but I believe it is the same thing. Is this OK?

smile.amazon.com

Crucial 32GB Kit (16GBx2) DDR4 2666 MT/s (PC4-21300) DR x8 SODIMM 260-Pin Memory - CT2K16G4SFD8266

CT16G4SFD824A is a 16GB DDR4 Notebook module that operates at speeds up to 2400 MT/s and has a CL17 latency. It is an buffered SODIMM. It conforms to the industry standard DDR4 SODIMM layout of 260 pins and is compatible with systems that take DDR4 2400MT/s SODIMM memory.
smile.amazon.com
 
pldelisle

pldelisle

macrumors 68020
Original poster
May 4, 2020
2,248
1,506
Montreal, Quebec, Canada
They will be compatible, but not certified for Mac. If you need support in the future, they won't back you. https://www.amazon.ca/Crucial-16GBx.../B07TKZKPJV/ref=sr_1_1?tag=macr05-20&dchild=1 is the good one, fully certified. But those you linked will work as other tested it. Choice is up to you.

EDIT : The certified Mac SKU is virtually not available anywhere in Canada. This is crazy how popular this kit became in the last weeks. In this case I'd date the generic model.
 
N

ninecows

macrumors 6502a
Apr 9, 2012
760
1,249
One thing I dont get:

Apple says PC4-21333 Ram on their webpage.

I can only find PC4-21300 ram.

Is it just a typo from Apples side? Does it matter?
 
N

neuralengine

macrumors regular
Jul 13, 2020
141
72
I currently have 32GB of Crucial CT2K16G4S266M (2 x 16 GB) and wanted to add another 2 x 16 GB but as pointed out by others it’s currently sold out/backordered everywhere in Canada.

When it’s back in stock, is it possible the batch difference will be an issue given how sensitive the 2020 iMac is to the DIMMs being exactly the same? Just wondering if I should get 4 x 16 GB from elsewhere or wait for the Crucial stuff to be back in stock. I can’t imagine I can mix this with the non-M variant.
 
pldelisle

pldelisle

macrumors 68020
Original poster
May 4, 2020
2,248
1,506
Montreal, Quebec, Canada
neuralengine said:
I currently have 32GB of Crucial CT2K16G4S266M (2 x 16 GB) and wanted to add another 2 x 16 GB but as pointed out by others it’s currently sold out/backordered everywhere in Canada.

When it’s back in stock, is it possible the batch difference will be an issue given how sensitive the 2020 iMac is to the DIMMs being exactly the same? Just wondering if I should get 4 x 16 GB from elsewhere or wait for the Crucial stuff to be back in stock. I can’t imagine I can mix this with the non-M variant.
Click to expand...
Wait for it. It's the best I can tell you. For best results, don't mix SKU. It should be back in stock in a couple of weeks.
 
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C

ClarkeLee

macrumors newbie
Sep 16, 2020
3
1
Just bought two Crucial 32gb rams, CT2K32G4SFD8266, and have them running on iMac 2020 for two days.
So far, so good.
WechatIMG52.jpeg WechatIMG50.jpeg

Screen Shot 2020-09-17 at 11.03.29 AM.png DiskSpeedTest.png
 
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G

GoYankees

macrumors member
Dec 17, 2012
30
8
longtom said:
What about Elite?
Shouldn‘t all RAM with the right specs be OK?
TeamGroup Elite SO-DIMM 32GB, DDR4-2666, CL19-19-19-43 (TED432G2666C19-S01)
www.teamgroupinc.com

ELITE SO-DIMM DDR4 laptop memory module

ELITE SO-DIMM DDR4 laptop memory module, All new generation product of DRAM module
www.teamgroupinc.com www.teamgroupinc.com
Click to expand...

I would avoid these. They do boot at 2666Mhz but performance was subpar. I ended up replacing them with the Timetec 32GB for Mac kit as the Crucials are sold out.

Geekbench scores for i7 5500xt:
Elite - 8040
Timetec - 8800

The Timetec scores are on par with previous good reports.
 
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L

longtom

macrumors member
Jun 11, 2013
72
16
GoYankees said:
I would avoid these. They do boot at 2666Mhz but performance was subpar. I ended up replacing them with the Timetec 32GB for Mac kit as the Crucials are sold out.

Geekbench scores for i7 5500xt:
Elite - 8040
Timetec - 8800

The Timetec scores are on par with previous good reports.
Click to expand...

Thanks!
Is there any indication what to look for that the RAM is well handled by the MAC?
 
L

longtom

macrumors member
Jun 11, 2013
72
16
OK, ordered now 128gb: 2x Crucial CT2K32G4SFD8266 64GB Kit (32GB x2) Speicher (DDR4, 2666 MT/s, SODIMM, 260-Pin, 1.2V, CL19).
 
nmikhail

nmikhail

macrumors newbie
Apr 1, 2019
3
2
don't have certified crucial ram for mac in Russia

found this though CT16G4SFRA266, the only difference is certification? will this memory work with new imac?
 
PBG4 Dude

PBG4 Dude

macrumors 601
Jul 6, 2007
4,362
4,645
longtom said:
OK, ordered now 128gb: 2x Crucial CT2K32G4SFD8266 64GB Kit (32GB x2) Speicher (DDR4, 2666 MT/s, SODIMM, 260-Pin, 1.2V, CL19).
Click to expand...
Pretty sure you need 4x32GB to get 128GB RAM. It’ll be interesting to see if you get the 64GB chips to work.

Bad reading comprehension.
 
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