What Ram to order with the new 2019 IMac?

Potts17

macrumors newbie
Original poster
Mar 20, 2019
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0
So what RAM package is everyone ordering? Assuming 32gb? What brands/model #’s do you recommend? Just ordered the 27” with 8gb of factory ram.
 

sandylp

macrumors 6502
Jul 10, 2004
259
11
San Francisco Bay Area
I ordered: 64.0GB (4x 16GB) PC4-21300 DDR4 2666MHz SO-DIMM 260 Pin Memory Upgrade Kit for 2019 iMac models which utilize PC4-21300 SO-DIMM from macsales.com You can also order 32GB in either 2x16GB or 4x8GB.
 
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macduke

macrumors G4
Jun 27, 2007
10,969
14,675
Central U.S.
So what RAM package is everyone ordering? Assuming 32gb? What brands/model #’s do you recommend? Just ordered the 27” with 8gb of factory ram.
I ordered this: https://smile.amazon.com/Crucial-16GBx2-PC4-21300-SODIMM-260-Pin/dp/B071H38422

It’s $30 cheaper than MacSales and seems to be the correct speed and pin layout. Furthermore people seem to have had no problem installing it into the new Mac Mini and I’ve had good luck with Crucial in the past. Make sure you keep your 8GB because there are four slots. Then you can have matched channel pairings to get full speed at 40GB, which is what I’m doing.
 

adamjackson

macrumors 68000
Jul 9, 2008
1,768
2,789
Remember too, the iMac 27" has 4 SO-DIMM slots so you can keep the two matched pairs of 4GB Ram (8GB) and add 32GB for a total of 40GB. I'll go 64GB if and when I actually need that much RAM. Have 32GB on my MacBook Pro and sometimes start to touch the ceiling but it happens so infrequently that I think 32GB is more than most people will ever functionally need except for VR/Science Modeling or massive video projects.

32GB for $199 + 8GB included is 40GB and is a ton (as of this writing in 2019, don't quote me in 10 years on my statement).
 

shaunp

Cancelled
Nov 5, 2010
1,811
1,394
I'd wait for the reviews/issues to become public, then order the lowest amount of RAM and buy the additional RAM from Crucial at half the price Apple will charge for essentially the same RAM.
 

macduke

macrumors G4
Jun 27, 2007
10,969
14,675
Central U.S.
Buy the new iMac with 8gb of RAM (for now).
Sit back 4-6 weeks until "RAM issues" become known (if they are to become known).

THEN consider buying more RAM...
I'd wait for the reviews/issues to become public, then order the lowest amount of RAM and buy the additional RAM from Crucial at half the price Apple will charge for essentially the same RAM.
The RAM I linked to above from Crucial doesn't seem to have any issues with the 2018 Mac Mini that uses the same 2666MHz speed and even works in older 2017 iMacs that came with 2400MHz. I'd be pretty shocked if I have any issues with what I purchased. You guys can use me as a guinea pig if you want, but I can always send it back if it has problems and it's only $199. I don't think I could get by for very long on 8GB, lol.

Also, it looks like someone asked them and the manufacturer responded on Amazon:

Is the compatible with the latest 2019 iMac?

Answer:
Thank you for contacting us and for your question. I have looked up this system and found that part number CT2K16G4SFD8266 does show as compatible with the 2019 iMac.
 

SaSaSushi

macrumors 601
Aug 8, 2007
4,104
497
Takamatsu, Japan
The RAM I linked to above from Crucial doesn't seem to have any issues with the 2018 Mac Mini that uses the same 2666MHz speed and even works in older 2017 iMacs that came with 2400MHz. I'd be pretty shocked if I have any issues with what I purchased. You guys can use me as a guinea pig if you want, but I can always send it back if it has problems and it's only $199. I don't think I could get by for very long on 8GB, lol.
Crucial is an excellent choice. It is, after all, the consumer division of Micron, Apple's primary vendor. I've seen far fewer reports of issues with Crucial than OWC over the years in these forums.
 

shaunp

Cancelled
Nov 5, 2010
1,811
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The RAM I linked to above from Crucial doesn't seem to have any issues with the 2018 Mac Mini that uses the same 2666MHz speed and even works in older 2017 iMacs that came with 2400MHz. I'd be pretty shocked if I have any issues with what I purchased. You guys can use me as a guinea pig if you want, but I can always send it back if it has problems and it's only $199. I don't think I could get by for very long on 8GB, lol.

Also, it looks like someone asked them and the manufacturer responded on Amazon:
There won't be issues with the RAM, that wasn't what I was referring to when I said 'issues'. I was referring to the iMac. so far an 8-core CPU in that iMac case is untested - it could thermal throttle a lot, or it could be okay. Wait for the reviews before ordering
 

remiller

macrumors newbie
Mar 22, 2019
17
2
USA
Planning purchase of 32 gb RAM, 2 x 16gb, from OWC. Would use the two stock 4gb modules as well for total 40gb RAM. My question is which slots to use for each of these? I guess these need to be paired in some way. In which slots should the larger modules be placed?
 
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adamjackson

macrumors 68000
Jul 9, 2008
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Planning purchase of 32 gb RAM, 2 x 16gb, from OWC. Would use the two stock 4gb modules as well for total 40gb RAM. My question is which slots to use for each of these? I guess these need to be paired in some way. In which slots should the larger modules be placed?
If you add two 16GB sticks in the two empty slots to an 8GB iMac, you'll have 40GB. They are 4 slots, two matched pairs so

Two 4GB Sticks
Two 16 GB Sticks
=40
 

eatmyjustice

macrumors member
Mar 24, 2008
41
4
Washington, USA
I ordered this: https://smile.amazon.com/Crucial-16GBx2-PC4-21300-SODIMM-260-Pin/dp/B071H38422

It’s $30 cheaper than MacSales and seems to be the correct speed and pin layout. Furthermore people seem to have had no problem installing it into the new Mac Mini and I’ve had good luck with Crucial in the past. Make sure you keep your 8GB because there are four slots. Then you can have matched channel pairings to get full speed at 40GB, which is what I’m doing.
Thanks for the link... I just ordered this too.
 
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Crylex

macrumors newbie
Mar 24, 2019
3
5
Philippines
Hi guys! Need your help. I just ordered a BTO iMac 27" and I want to buy another 32gb ram for it.
The problem is I do now know which is compatible and which is not. Its my first time having a mac and upgrading a ram.

I checked the internet and found these:

OWC 32GB Ram ~ 230 USD
https://eshop.macsales.com/item/OWC/2666DDR4S32P/

Crucial 32GB DDR4 2400 MHz SO-DIMM Memory Module Kit ~ 199 USD
https://www.bhphotovideo.com/c/product/1346254-REG/crucial_ct2k16g4s24am_32gb_kit_16gb_x2.html

G.Skill SODIMM 32GB ~ 230 USD

I honestly do not know which is the better option among those 3 so please help me. And if you can suggest a different one, please do so.
Appreciate all the help! Thank you!
 

sandylp

macrumors 6502
Jul 10, 2004
259
11
San Francisco Bay Area
Hi guys! Need your help. I just ordered a BTO iMac 27" and I want to buy another 32gb ram for it.
The problem is I do now know which is compatible and which is not. Its my first time having a mac and upgrading a ram.

I checked the internet and found these:

OWC 32GB Ram ~ 230 USD
https://eshop.macsales.com/item/OWC/2666DDR4S32P/

Crucial 32GB DDR4 2400 MHz SO-DIMM Memory Module Kit ~ 199 USD
https://www.bhphotovideo.com/c/product/1346254-REG/crucial_ct2k16g4s24am_32gb_kit_16gb_x2.html

G.Skill SODIMM 32GB ~ 230 USD

I honestly do not know which is the better option among those 3 so please help me. And if you can suggest a different one, please do so.
Appreciate all the help! Thank you!
You need The DDR4 2666 MT/s (PC4-21300) DR x8 Sodimm 260 - Pin Memory. Looks like the most inexpensive place is Amazon. https://www.amazon.com/Crucial-16GBx2-PC4-21300-SODIMM-260-Pin/dp/B071H38422?pldnSite=1
 
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Rockadile

macrumors 6502
Jun 11, 2012
454
184
Planning purchase of 32 gb RAM, 2 x 16gb, from OWC. Would use the two stock 4gb modules as well for total 40gb RAM. My question is which slots to use for each of these? I guess these need to be paired in some way. In which slots should the larger modules be placed?
Put the larger RAM modules where the stock ones were.
 

SaSaSushi

macrumors 601
Aug 8, 2007
4,104
497
Takamatsu, Japan
Put the larger RAM modules where the stock ones were.
So long as the matching DIMMs are installed in alternating slots (dual channel) it makes no difference which set goes where in terms of performance.

I added 32GB (2x16GB) to my 2017 iMac and benchmarked it with no difference aside from a marked decrease when the matching DIMMs were not in proper dual-channel configuration.

You can just put the new modules into the empty slots.
 

Rockadile

macrumors 6502
Jun 11, 2012
454
184
So long as the matching DIMMs are installed in alternating slots (dual channel) it makes no difference which set goes where in terms of performance.

I added 32GB (2x16GB) to my 2017 iMac and benchmarked it with no difference aside from a marked decrease when the matching DIMMs were not in proper dual-channel configuration.

You can just put the new modules into the empty slots.
Since I was going by a PC motherboard manual, by all means put the new ones in the empty slots if there are no difference with a iMac logic board.
 
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mikey8811

macrumors member
Mar 23, 2019
94
12
On the base 27 in iMac, it says the maximum RAM is 32 Gb.

I was initially thinking of keeping the 2 x 4 Gb that comes with it and adding another 2 x 16 Gb for 40 Gb in total later like some of you have done here. I presume that isn't possible.

So I presume if I wish to keep the original RAM, the best that I can do is add another 2 x 8 Gb for a maximum of 24 Gb? is this correct?

Thanks
 

curmudgeonette

macrumors 6502a
Jan 28, 2016
549
405
California
On the base 27 in iMac, it says the maximum RAM is 32 Gb.

I was initially thinking of keeping the 2 x 4 Gb that comes with it and adding another 2 x 16 Gb for 40 Gb in total later like some of you have done here. I presume that isn't possible.
The "limit" is simply because Apple doesn't want to provision base model machines with maximum memory. This would be an SKU that sells very little. The base model is also not available with an i9 CPU nor the biggest Fusion drive.

Go right ahead and upgrade to 40GB.
 
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jonatious

macrumors member
Sep 29, 2016
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Last edited:

charliedread

macrumors newbie
Mar 26, 2019
1
0
Can I use the ram 2400 from the previous imac and mix it with the 2666 in the new 2019 imac? I heard you can but the 2666 is going to get downclock to 2400.
 

Chancha

macrumors 6502a
Mar 19, 2014
941
830
Off on a Hong Kong forum, some guy's iMac already arrived.
The stock RAMs are 4+4GB sticks of SK hynix HMA851S6CJR6N-VK
PC4-21300 2666MHz 1.2V 0.75ns CL19
 
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