OWC RAM Issue? 128gb Configuration

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OWC RAM Issue? 128gb Configuration

Let me preface this by saying I'm not a tech person, so go easy on me with verbiage/competency. I have a 2019 27 inch 4k iMac with 3.7 GHz 6-core. Flash hard drive.

I bought third party 128gb of RAM from OWC, 4x32gb. The Mac itself said 64 max, but OWC assured me 128 was fine. Since installing, the computer seems to hibernate incorrectly; it just stays frozen and I have to do a manual reboot. I then get sleep-wake failure in EFI report. I also had one instance where I had a panic log. I forget the exact verbiage.

When I tried updating to the new OS (from Big Sur), it rebooted itself several times, and was still in Big Sur.

I never had an issue with the Mac prior to the RAM swap.

Is this normal? Is it because I went to 128gb? Is it just bad ram, and I should ask for replacement?

Thanks for any (hopefully dumbed down) advice.

iMac 27″, macOS 11.5

Posted on Nov 25, 2021 2:22 PM

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Answer 1

Top-ranking reply

den.thed

Level 10

84,610 points

Nov 25, 2021 7:00 PM in response to aolk

Yes that would tell you if there is a bad 32GB module in the bunch.

However I suspect that you may find, that the iMac just doesn't like having a full boat of 32GB modules.

Also keep in mind that Apple says 64GB

https://support.apple.com/en-us/HT201191

and that Crucial for only sells 16GB modules for the 2019 27" iMac.

https://www.crucial.com/compatible-upgrade-for/apple/imac-%28retina-5k--27-inch--2019%29-imac-19-1

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Answer 2

den.thed

Level 10

84,610 points

Nov 25, 2021 3:28 PM in response to aolk

Make sure that all of the 32GB modules are firmly seated in the slots and re-test.
Then if it act up, test it with the 2 stock modules in their original slots and 2 32GB modules in the previously empty slots.
You might also want to test it with 1 of the original modules and 3 32GB modules before contacting OWC Support for assistance.

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Answer 3

rkaufmann87

Level 10

146,448 points

Nov 25, 2021 2:25 PM in response to aolk

Why do you feel you need 128GB of RAM? 99% of the people out there don't. I would return the 128GB DIMMs to OWC and exchange for a smaller amount. I operate my 2020 27" iMac with 40GB and never have RAM issues.

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Answer 4

aolk Author

Level 1

8 points

Nov 25, 2021 2:36 PM in response to rkaufmann87

My question isn't whether it's excessive. I'm asking if my suspicion that the RAM can cause these issues is correct. It didn't happen prior to the swap.

As far as amount...it's probably excessive, but I also run some fairly intensive software, and I leave a lot of programs open at once.

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Answer 5

babowa

Level 9

78,477 points

Nov 25, 2021 4:04 PM in response to aolk

FWIW, unless you are using Final Cut (or similar) and rendering videos 24/7, 128 GB of RAM is a serious overkill. My own experience is that doubling the max RAM supported is not necessarily a good thing.

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Answer 6

den.thed

Level 10

84,610 points

Nov 25, 2021 7:54 PM in response to aolk

Does it work OK on the 2 original modules and 2 32GB modules?

Did you test 1 original module and 3 32GB modules?

(that would suggest it can actually use over 64GB)

At this point, I highly recommend contacting OWC Support in the morning.

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Answer 7

aolk Author

Level 1

8 points

Nov 25, 2021 4:05 PM in response to den.thed

Thanks - I'll give that a go. A friend suggested I individually try each 32gb module to see if I can isolate the issue.

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Answer 8

aolk Author

Level 1

8 points

Nov 25, 2021 7:32 PM in response to den.thed

I’m definitely concerned about that part…

I found a few sites claiming it was fine, and OWC says so as well, but exceeding the rec’d 64 is a little worrisome.

I think 64 would be more than ample.

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Answer 9

aolk Author

Level 1

8 points

Nov 26, 2021 10:44 AM in response to den.thed

I isolated one stick which seems to be the issue. I'm going to send 2 back and use it as 64 (hopefully).

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Answer 10

babowa

Level 9

78,477 points

Nov 26, 2021 11:02 AM in response to aolk

I'd go with no more than a 16 GB module per slot - but that is my opinion. It isn't just the total amount that could be a problem, but the individual slot capacity as well.

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