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vfontjr

macrumors newbie
Original poster
Oct 23, 2019
23
8
Raleigh, NC
I had nothing but problems after installing Mac OS Catalina on a brand-new maxed out 2019 iMac 27" 5K. The machine, as I write this, is barely 2-weeks old. As you know, Apple charges a premium price for RAM updates. So I did what many do, I bought this machine with 8Gb and upgraded it to 128Gb when it arrived using a RAM upgrade kit from OWC.

The KPs and reboots were endless. Apple's built-in hardware diagnostics said everything was working correctly. So, I decided to take the iMac back to its delivered OS, Mojave. But with Mojave, I started experiencing KPs as well. Now, I'm beginning to suspect a hardware issue and reached out to OWC tech support. Here's what OWC said after I contacted them:

"Occasionally in the manufacturing process, a module may get splashed with a manufacturing solution that can cause difficulties mounting once installed into the customer's computer. One of the most common ways that this occurs is that the system will be able to boot up fine and the modules will pass basic testing, but you'll get intermittent crashing - it will attempt to utilize a section of the module that is being obscured and this will cause the sudden crash."

The tech support specialist provided instructions on how to clean the RAM and run deeper memory testing using Rember after reinstalling it. The OWC RAM caused a kernel panic every time I tried to run Rember. It would get to different points in the process and fail every time. Keep in mind, this RAM passed Apple's internal hardware testing.

I removed the OWC RAM and reinstalled the Apple supplied 8Gb RAM and ran Rember again. This time the machine passed all deep hardware testing and has been stable since. The machine is still running Mojave and the bad RAM is on the way back to OWC for replacement. I haven't dared to upgrade to Catalina again, but perhaps I shall after the next one or two point releases. Hope this is helpful.
 
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anthonymoody

macrumors 68030
Aug 8, 2002
2,805
942
I had nothing but problems after installing Mac OS Catalina on a brand-new maxed out 2019 iMac 27" 5K. The machine, as I write this, is barely 2-weeks old. As you know, Apple charges a premium price for RAM updates. So I did what many do, I bought this machine with 8Gb and upgraded it to 128Gb when it arrived using a RAM upgrade kit from OWC.

The KPs and reboots were endless. Apple's built-in hardware diagnostics said everything was working correctly. So, I decided to take the iMac back to its delivered OS, Mojave. But with Mojave, I started experiencing KPs as well. Now, I'm beginning to suspect a hardware issue and reached out to OWC tech support. Here's what OWC said after I contacted them:

"Occasionally in the manufacturing process, a module may get splashed with a manufacturing solution that can cause difficulties mounting once installed into the customer's computer. One of the most common ways that this occurs is that the system will be able to boot up fine and the modules will pass basic testing, but you'll get intermittent crashing - it will attempt to utilize a section of the module that is being obscured and this will cause the sudden crash."

The tech support specialist provided instructions on how to clean the RAM and run deeper memory testing using Rember after reinstalling it. The OWC RAM caused a kernel panic every time I tried to run Rember. It would get to different points in the process and fail every time. Keep in mind, this RAM passed Apple's internal hardware testing.

I removed the OWC RAM and reinstalled the Apple supplied 8Gb RAM and ran Rember again. This time the machine passed all deep hardware testing and has been stable since. The machine is still running Mojave and the bad RAM is on the way back to OWC for replacement. I haven't dared to upgrade to Catalina again, but perhaps I shall after the next one or two point releases. Hope this is helpful.

Some of the people getting KPs in other threads seem to have been able to tie it to a non-OEM SSD replacement rather than RAM. Could be related I suppose.
 

dogslobber

macrumors 601
Oct 19, 2014
4,549
7,589
Apple Campus, Cupertino CA
I removed the OWC RAM and reinstalled the Apple supplied 8Gb RAM and ran Rember again. This time the machine passed all deep hardware testing and has been stable since. The machine is still running Mojave and the bad RAM is on the way back to OWC for replacement. I haven't dared to upgrade to Catalina again, but perhaps I shall after the next one or two point releases. Hope this is helpful.
If you identified the hardware as being the issue then why the concern about Catalina? BTW, thanks for the reference to Rember. Not came across that before.
 

harriska2

macrumors 68000
Mar 16, 2011
1,531
737
Oregon
I also got Crucial and haven’t had problems (with mojave at least). I know people had KP with 2018 minis even running mojave.
 

bob_stan

macrumors regular
Oct 6, 2019
119
73
Central New York
I have had little trouble with OWC RAM. My 2013 MacPro has 64GB of OWC ram. One 16GB module failed a memory check after 3 years and they replaced all 64GB under their lifetime warranty with no questions at all.
 
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vfontjr

macrumors newbie
Original poster
Oct 23, 2019
23
8
Raleigh, NC
If you identified the hardware as being the issue then why the concern about Catalina? BTW, thanks for the reference to Rember. Not came across that before.

Simple, because going back to Mojave is a nightmare of a task if upgrading to Catalina fails again. At this point, I'm a little gun-shy.
 

drlunanerd

macrumors 68000
Feb 14, 2004
1,678
173
UK
I swore I'd never buy anything again from OWC many years ago and I've stuck to that promise.
 

28Gauge

macrumors 6502a
Sep 4, 2011
694
416
DFW
While researching additional RAM for my 2109 iMac, I ran across several posts where people where having some trouble with OWC branded RAM. I went with Crucial and have not had any issues. I have the factory 8GB of RAM along with 32GB of Crucial.
 

SoCalReviews

macrumors 6502a
Dec 31, 2012
582
210
While researching additional RAM for my 2109 iMac, I ran across several posts where people where having some trouble with OWC branded RAM. I went with Crucial and have not had any issues. I have the factory 8GB of RAM along with 32GB of Crucial.
Good choice. Crucial has been an official Apple Mac OEM memory supplier for many years. I've never had an issue with their RAM and I always get their Mac recommended model specific spec matched pair memory kits.
 
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tarsins

macrumors 6502a
Sep 15, 2009
983
722
Wales
Not using any third-party RAM on either my MacBook Pro (16GB) or my iMac (32GB) and Catalina is running fine on both. Yes, I know Apple's RAM is expensive, but at the end of the day it's worth it to have a hassle-free experience.
 

MacManiac76

macrumors 68000
Apr 21, 2007
1,646
422
White Mntns, Arizona
Not using any third-party RAM on either my MacBook Pro (16GB) or my iMac (32GB) and Catalina is running fine on both. Yes, I know Apple's RAM is expensive, but at the end of the day it's worth it to have a hassle-free experience.

Technically the RAM Apple uses is still 3rd-party RAM, at least in the iMac. The RAM in the iMac is usually from Hynix and occasionally from another 3rd party. Unless the MacBook Pro's RAM is the soldered on RAM, then it is technically 3rd-party as well. As long as you match up the RAM specs to what the computer comes with initially, you will not have any problems, unless the RAM is defective.
 
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