Memory upgrade troubleshooting in 2020 27-inch iMacs

[AZREOSpecialist]

I believe the iMac 20,2 are those with the 5700XT GPU (or 5700 GPU?). Don't know why, maybe the logic board is different to accommodate the different GPU.
It's not as if 20,2 is a later version of 20,1 as they both came out the same time.
I may be wrong, which would be proven if someone has a 5700XT GPU and their model identifier is not 20,2.

10- core w/5700xt here and shows iMac20,2 in System Report.

 

[LGR]

There is something seriously wrong with this chart. How can mixed 40 GB at 2667 MHz be over 40% slower than the same mixed 40 GB at 2133 MHz? I don't think this chart is correct.

Because dual channel is lost.

 

[LGR]

I installed 4 X 32 exact amtching sims from OWC macsales and they are running 2666 and dual channel. I asked then to be sure i got 4 exact sims and they did.

 

[Bechi]

I believe the iMac 20,2 are those with the 5700XT GPU (or 5700 GPU?). Don't know why, maybe the logic board is different to accommodate the different GPU.
It's not as if 20,2 is a later version of 20,1 as they both came out the same time.
I may be wrong, which would be proven if someone has a 5700XT GPU and their model identifier is not 20,2.

I see. This was the first time I had seen those designations so I thought they may have indicated some change in design, ie the "old" 2019 iMacs issued in 2020 vs. the "new" 2020 iMacs issued in 2020. Thanks for the clarification!

 

[victry1]

I received my 32GB RAM from OWC. Just want to double check before I install - I remove the 16GB that came in the computer and install the new in the same slots?

I will say that with the 16GB I'm surprised I've gotten the beach ball several times along with a low resource warning. I'm wondering if that is because it has more cores (8) than any other device I've owned.

 

[pldelisle]

I will say that with the 16GB I'm surprised I've gotten the beach ball several times along with a low resource warning. I'm wondering if that is because it has more cores (8) than any other device I've owned.

No. Something you use just takes a lot of memory.
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I received my 32GB RAM from OWC. Just want to double check before I install - I remove the 16GB that came in the computer and install the new in the same slots?

Yes.

 

[victry1]

No. Something you use just takes a lot of memory.
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Yes.

Thank you, pdlelisle. I wasn't running anything that is a resource hog which is why I noticed, but, hopefully with the new RAM I won't see that anymore. After reading more in this thread I'm kind of wishing I ordered 64GB but things are tight around here at the moment so 32GB will have to do.

 

[mikehalloran]

Thank you, pdlelisle. I wasn't running anything that is a resource hog which is why I noticed, but, hopefully with the new RAM I won't see that anymore. After reading more in this thread I'm kind of wishing I ordered 64GB but things are tight around here at the moment so 32GB will have to do.

If you ordered 16x2, you can always order another pair later.

 

[AZREOSpecialist]

Because dual channel is lost.

Thanks, I didn't catch that distinction. Makes sense now.

 

[AZREOSpecialist]

I received my 32GB RAM from OWC. Just want to double check before I install - I remove the 16GB that came in the computer and install the new in the same slots?

I will say that with the 16GB I'm surprised I've gotten the beach ball several times along with a low resource warning. I'm wondering if that is because it has more cores (8) than any other device I've owned.

Forgive me for not reading prior pages if this has been addressed, but the stock 2020 iMac comes with 8 GB (2 x 4 GB), not 16 GB. I would expect a lot of beachballs with only stock 8 GB RAM.

 

[victry1]

Forgive me for not reading prior pages if this has been addressed, but the stock 2020 iMac comes with 8 GB (2 x 4 GB), not 16 GB. I would expect a lot of beachballs with only stock 8 GB RAM.

unfortunately, I ordered it with the 16gb before I knew I would have to discard them In order to increase theRAM.

 

[pldelisle]

unfortunately, I ordered it with the 16gb before I knew I would have to discard them In order to increase theRAM.

That is costly....

 

[mikehalloran]

unfortunately, I ordered it with the 16gb before I knew I would have to discard them In order to increase theRAM.

I’m not so sure. Apple uses Micron. Micron is also one of OWC’s vendors. If the pair of 16s you ordered won’t give you the performance you require, why can’t you return and order a pair directly from Crucial, Micron’s retail arm? Did you buy from someone who doesn’t accept returns?

The T2 chip doesn’t register the sticker on the RAM sticks. As long as all 4 sticks are the same size and meet the spec required by the 2020, you should be good.

We have learned that much RAM that works perfectly well in the 2019 doesn’t mix well when combined with the OE Micron RAM in the 2020.

If I decide to upgrade my 2020 with another pair of 16GB sticks and they don’t match perfectly in all respects, the first pair goes back under the OWC warranty.

This has happened before. I don’t recall how many years ago but a MacOS upgrade gave errors in a whole lot of MacBooks that had upgraded RAM. Fortunately, I’d bought all of it from OWC and they overnighted replacement sticks to me. We’re talking over 100 MacBooks that belonged to a school district.

 

[AZREOSpecialist]

unfortunately, I ordered it with the 16gb before I knew I would have to discard them In order to increase theRAM.

You shouldn't be beach-balling with 16 GB. Were you processing a really large file in Photoshop or something?

 

[getrealbro]

When I added a pair of 16GB Crucial RAM to my friend's new 2020 iMac, the "Memory Slots" in the System Report said the manufacture was “859B”. And the manufacturer of the original 8GB of Apple RAM was “Micron”.



FWIW i have the same 32GB of Crucial RAM in my 2018 Mini and it too shows a manufacturer of “859B” not Micron.

GetRealBro

 

[fullhd]

Hello,

I'm still waiting for my own DIY memories. This will be 64 GB. Currently 8 GB.
However, I diminish the current test result.

iMac 20.2 (i7 3.8 GHz 8 core, currently default 8 GB RAM, GPU 5700 XT)

Single-core: 1270
Multi-Core: 7566

Is the multi result not low or normal?
(After the memory upgrade I'll post my new test result.)

 

[victry1]

You shouldn't be beach-balling with 16 GB. Were you processing a really large file in Photoshop or something?

I had 2-3 programs open, probably Lightroom, not PS. Nothing really a resource hog. Fortunately, it doesn't spin really long but I don't think it should spin at all. My 2015 MBP doesn't do that. Hopefully, it will improve once I add more RAM.

 

[wilberforce]

Hello,

I'm still waiting for my own DIY memories. This will be 64 GB. Currently 8 GB.
However, I diminish the current test result.

iMac 20.2 (i7 3.8 GHz 8 core, currently default 8 GB RAM, GPU 5700 XT)

Single-core: 1270
Multi-Core: 7566

Is the multi result not low or normal?

That looks "normal" in that it is consistent with scores others report for i7 with only 8GB RAM.
However you should get about 8900 multi-core when you have 64GB.
See:

iMac20, - Geekbench 5 CPU Search - Geekbench

(you have to click on individual results to see amount of RAM)

 

[victry1]

I dl Geekbench today and this is the score with 16GB of RAM. I will do another once I install the new RAM. I don't know if this is a good score or not.

 

[wilberforce]

I dl Geekbench today and this is the score with 16GB of RAM. I will do another once I install the new RAM. I don't know if this is a good score or not. View attachment 954208

Looks OK, assuming this is an i7. I suggest run it at least 3 times and take the maximum. This helps avoid some background process reducing your score

 

[fullhd]

That looks "normal" ...
See:

iMac20, - Geekbench 5 CPU Search - Geekbench

(you have to click on individual results to see amount of RAM)

Thanks for the reassuring link.

 

[PBG4 Dude]

I dl Geekbench today and this is the score with 16GB of RAM. I will do another once I install the new RAM. I don't know if this is a good score or not. View attachment 954208

If you’re worried about RAM speeds, run Novabench. If your RAM is set up correctly, you should achieve about 28000MB/s.

 

[panjandrum]

Just installed OWC 32GB and I also get 2133mhz when leaving in the Apple ram. So what is everyone’s final decision who isn’t buying new ram? My assumption is it’s better to have 40gb at 2133 than just the 32GB at 2666 and putting the Apple memory in a drawer. Thoughts?

From the gaming benchmarks I've seen it takes a significant memory speed difference to see ANY performance difference even in extremely demanding applications. At a guess you are going to be better off with more memory at a very slightly reduced speed. But as others have mentioned, it's a big "depends on." If you really aren't using more than the 32, you might as well just stick with that at 2666.

 

[wilberforce]

From the gaming benchmarks I've seen it takes a significant memory speed difference to see ANY performance difference even in extremely demanding applications. At a guess you are going to be better off with more memory at a very slightly reduced speed. But as others have mentioned, it's a big "depends on." If you really aren't using more than the 32, you might as well just stick with that at 2666.

Also see post #409, and post #422, as another data point

 

[fullhd]

I just installed my memory upgrade.
System: iMac 20.2 (i7 3.8 GHz 8 core, GPU 5700 XT)

I bought Kingston memory which is system specific memory for iMac 2020.
64 GB RAM (4 x 16 GB) [Kingston - KCP426SD8/16]
Kingston System Specific Memory for iMac 2020

My test result with default 8 GB:

Novabench RAM test with 8 GB:

My test result with 64 GB (DIY):

Novabench RAM test with 64 GB:

Anyway, this is also worth looking into if you haven’t decided on RAM yet.
Best combination of memory for the 2020 iMac