Problems with installing new memory in the new 2020 27" iMac

[camner]

I ordered 2x32GB kit from OWC to replace the stock 8GB RAM. I couldn't get the iMac to boot with the OWC RAM. I put the original Apple sticks back in, and the computer wouldn't boot then, either. After a number of attempts (about 6), I finally got the iMac to boot with the stock memory. It appears that my new iMac is very sensitive to exactly how the DIMM sticks are positioned (at least that's the only thing I can think of to explain it).

I then tried adding the OWC memory to slots 1 & 3 withOUT removing the Apple RAM, and lo and behold, the iMac booted! But try as I might, I couldn't get the iMac to boot with OWC memory only in the machine.

So, I then put back in all 4 sticks (2xApple + 2xOWC), but it took a couple of tries to get the iMac to boot. I then removed the stock RAM from slots 2 & 4, leaving the OWC RAM in slots 1 & 3, and the iMac boots just fine. System Report says I've got 64GB running at 2666MHz.

So, two questions:

1. Is the VERY finicky nature of the RAM insertion/replacement process something I should think of as a defect worthy of taking up with Apple?
2. Is there any reason I shouldn't be happy with two OWC sticks in slots 1 & 3 instead of 2&4? I'm getting 2666MHz, I know. Am I getting dual channel with this config?

 

[Donnation]

Its funny to see this, as I had the exact same issue when I originally installed RAM in my 2020 iMac. I have memory in slots 1 and 3 as well, and initially the iMac would not boot. I could not figure out what the heck was going on. I even got Apple support involved. They didn't really know what the issue was, but after pulling the memory out and placing it in again it booted without issue.

Since then, its worked and booted on fine so I don't know what the heck the non booting is all about initially.

And to answer your question, yes you are getting dual channel in slots 1 and 3. As far as taking it up with Apple, they won't have any clue what you are talking about but will offer to send you a new one if you want (that's what they offered me). I told them no for now but if they issue came up again that I would be asking for a new unit to be sent out to me and they said that would be fine. As I said though, no issues since that initial problem.

 

[camner]

Thanks for your reassuring reply (well, reassuring about the slots, not so much about the iMac's finicky RAM replacement!)

 

[Silencio]

I'm curious about others' experiences with this. I have a couple of 2020 27" iMacs on the way, but I ordered 4x16GB SODIMMs to upgrade them to 64GB. We'll see if that makes a difference, though my systems aren't due to ship for another 7-10 days.

 

[Ruz]

I'm curious about others' experiences with this. I have a couple of 2020 27" iMacs on the way, but I ordered 4x16GB SODIMMs to upgrade them to 64GB. We'll see if that makes a difference, though my systems aren't due to ship for another 7-10 days.

I got 32GB from OWC (2x16GB). When the iMac came, I pulled out the Apple RAM and installed the OWC RAM in the same slots. Never had an issue with booting the machine.

 

[camner]

I got 32GB from OWC (2x16GB). When the iMac came, I pulled out the Apple RAM and installed the OWC RAM in the same slots. Never had an issue with booting the machine.

I have changed the RAM in countless Macs over decades (usually with RAM from OWC), including a previous 27” iMac (2015). I have NEVER had this kind of problem before. I know how to do this. Occasionally I had to reseat the RAM a second time. Nothing like this.

I hope this isn’t a sign of a machine that is “on the edge.” I did get AppleCare, so I have 3 years during which I can take it to Apple, but I intend to keep this machine longer, perhaps much longer.

 

[Zltnnd]

I ordered 2x32GB kit from OWC to replace the stock 8GB RAM. I couldn't get the iMac to boot with the OWC RAM. I put the original Apple sticks back in, and the computer wouldn't boot then, either. After a number of attempts (about 6), I finally got the iMac to boot with the stock memory. It appears that my new iMac is very sensitive to exactly how the DIMM sticks are positioned (at least that's the only thing I can think of to explain it).

I then tried adding the OWC memory to slots 1 & 3 withOUT removing the Apple RAM, and lo and behold, the iMac booted! But try as I might, I couldn't get the iMac to boot with OWC memory only in the machine.

So, I then put back in all 4 sticks (2xApple + 2xOWC), but it took a couple of tries to get the iMac to boot. I then removed the stock RAM from slots 2 & 4, leaving the OWC RAM in slots 1 & 3, and the iMac boots just fine. System Report says I've got 64GB running at 2666MHz.

So, two questions:

1. Is the VERY finicky nature of the RAM insertion/replacement process something I should think of as a defect worthy of taking up with Apple?
2. Is there any reason I shouldn't be happy with two OWC sticks in slots 1 & 3 instead of 2&4? I'm getting 2666MHz, I know. Am I getting dual channel with this config?

I had a similar problem with mine. Try pushing the memory modules inward as you rotate the whole assembly back into its locked position. Without the inward pressure the memory sticks tend to move back out when the assembly is rotated into locked position. And yes there is a stupid problem with these assemblies.

 

[pmiles]

Apple updated their RAM installation documentation on 9-2-2020 to address the issues customers are seeing with this Mac and RAM installation. In a nutshell, all sticks of RAM need to be identical in spec, capacity, and vendor in order to achieve dual channel support. If it interprets 2 sticks as being from manufacturer X and two from manufacturer Y even if the packaging that came with the RAM said they were all the same, it's not going to have dual channel support... it's considered mixed RAM.

Mixed RAM, capacity or manufacturer needs to be installed in slots 1&2 then 3&4.

Apple calls slots 1&2 Channel A and slots 3&4 Channel B.

The assumption is everyone is installing RAM in pairs of identicalness... so nothing has been said about only using 3 slots in the new machine or say 4 sticks of identical spec but different manufacturers. I suspect those scenarios would result in lower speeds being reported than they should be.

 

[camner]

I had a similar problem with mine. Try pushing the memory modules inward as you rotate the whole assembly back into its locked position. Without the inward pressure the memory sticks tend to move back out when the assembly is rotated into locked position. And yes there is a stupid problem with these assemblies.

Thanks for the tip. That wasn't necessary with my 2015 27" iMac; I just had to swing the arms back to the locked position. I'll try your suggestion.

 

[EvilCo_E]

I ordered the wrong ram at first (2x16gb) and it only ran at 2133Mhz (with and without the 8gb Apple ram), then I got 4x16gb of proper crucial ram and now it works perfectly at 2667Mhz. I've replaced the ram and fiddled around with it quite a few times but I've never had the machine not boot. One of the slots never really made a clicking sound like the rest did but it worked fine.

I've had a completely different sort of ram related ordeal, the ram door wouldn't fit in properly (one of the sides was sticking out) so I took it out and put it back and it stayed the same. So then when I pressed the button to release the door again 3 of the little hinges broke clean off the ram door. So now I'm stuck with a piece of paper on the hole to prevent dust from going in until my replacement door arrives. I think that's apples revenge for me not buying their ram Lol.

So yeah an unlucky day for me that was, although I just found it quite hilarious in the variety of problems I had with the ram replacement experience.

 

[lukasz74nj]

I ordered 2x32GB kit from OWC to replace the stock 8GB RAM. I couldn't get the iMac to boot with the OWC RAM.

In my case it took a very long time to boot (black screen, no sound) after replacing the memory but it is all good since then. It was more challenging to open the RAM door - Lego Technic, Liftarm (32017) does the job pretty well.

 

[camner]

In my case it took a very long time to boot (black screen, no sound) after replacing the memory but it is all good since then. It was more challenging to open the RAM door - Lego Technic, Liftarm (32017) does the job pretty well.

How long was "a very long time." When I finally got it to boot, it was about 45 seconds the first time it booted.

 

[lukasz74nj]

How long was "a very long time." When I finally got it to boot, it was about 45 seconds the first time it booted.

I think it was about the same (black screen for 45 seconds or so).

 

[hellfried]

In my case I removed the Apple ram, replaced them with 8G x 2 of Crucial memory. It booted up after a small delay of about 5 seconds. One week later another 2 sticks of 8G Crucial memory arrived from a different vendor. After installing them the computer again took an extra 5 seconds to boot up and its all good. Now I have 32G of memory running at 2667 MHz.

 

[UFallingRock]

I had a similar problem with mine. Try pushing the memory modules inward as you rotate the whole assembly back into its locked position. Without the inward pressure the memory sticks tend to move back out when the assembly is rotated into locked position. And yes there is a stupid problem with these assemblies.

Thank you for your suggestion on pressing inwards as you rotate the assembly back into position. My first attempt at installation failed. Then I remembered your suggestion, and that worked on my second attempt. It appears that it is very easy to inadvertently unseat the memory when trying to lock it into position.

 

[petero221]

I have the 2020 27" iMac with two 4 GB RAM (2667MHz) from Apple installed in slots 1 (Channel A/DiMM1) and 3 (Channel B DiMM1). When I followed the instructions, and installed two OWC 16GB RAM chips (2667MHz) in the free slots (2 and 4), it told me that my Mac had 4 memory slots each of which accepts a 2133 MHz DDR4 memory module - which is clearly incorrect as the slots are 26667MHz! When I installed the 2 x 4GB Apple memory in slots 1 & 2 and the 2 x 16GB OWC in memory slots 3 & 4 it (correctly) told me that my Mac had 4 memory slots each of which accepts a 2667 MHz DDR4 memory module. So now I am completely non-plussed! I haven't use Geekbench or anything but if the Mac thinks it has 2133 MHz memory modules, surely this is a bad thing???? Or is this just a glitch in the Apple OS software and is it running at full speed? I settled with putting the memory in 1&2 and 3&4 respectively but then presumably it doesn't have dual channel support? HELP????

 

[Benz63amg]

I have the 2020 27" iMac with two 4 GB RAM (2667MHz) from Apple installed in slots 1 (Channel A/DiMM1) and 3 (Channel B DiMM1). When I followed the instructions, and installed two OWC 16GB RAM chips (2667MHz) in the free slots (2 and 4), it told me that my Mac had 4 memory slots each of which accepts a 2133 MHz DDR4 memory module - which is clearly incorrect as the slots are 26667MHz! When I installed the 2 x 4GB Apple memory in slots 1 & 2 and the 2 x 16GB OWC in memory slots 3 & 4 it (correctly) told me that my Mac had 4 memory slots each of which accepts a 2667 MHz DDR4 memory module. So now I am completely non-plussed! I haven't use Geekbench or anything but if the Mac thinks it has 2133 MHz memory modules, surely this is a bad thing???? Or is this just a glitch in the Apple OS software and is it running at full speed? I settled with putting the memory in 1&2 and 3&4 respectively but then presumably it doesn't have dual channel support? HELP????

You need to update all 4 modules with third party modules of same size and same brand, can’t mix with apple’s own Ram as you lose either speed or dual channel support

 

[petero221]

You need to update all 4 modules with third party modules of same size and same brand, can’t mix with apple’s own Ram as you lose either speed or dual channel support

On my 2017 27" iMac I happily mixed sizes - kept the two 4GB Apple ones and had 2 x 8GB OWC ones no problems!

 

[wilberforce]

On my 2017 27" iMac I happily mixed sizes - kept the two 4GB Apple ones and had 2 x 8GB OWC ones no problems!

This is very true on all iMacs except the 2020 iMac.

Apple itself has different memory upgrade instructions for the 2020 iMac, stating (for the 2020 iMac only): "For optimal memory performance, DIMMs should be the same capacity, speed, and vendor."

 

[tbird57]

Ok I just bought the imac 27 2020 put in two 16 OWC MODS with the stock left the stock in the slots they were in and installed OWC into the empty slots. My machine would reboot no matter what I did it would keep rebooting. put the stock in by them selves everything fine...put the OWC by them selfs reboots.. sent them back waiting for new ones. question? should I just run the two OWC only without the stock or try with both?

 

[camner]

Given all the commentary on the issue with mixing stock and 3rd party memory, I'd try just inserting the OWC memory and leave the stock memory out. Also, note that a number of people (including me!) have pointed out that getting the memory sticks to fully seat is no easy task! I had to try a number of times before it finally "took," and since then, I've left well enough alone! See post #7 above for @Zltnnd's comment about this.

 

[tbird57]

Given all the commentary on the issue with mixing stock and 3rd party memory, I'd try just inserting the OWC memory and leave the stock memory out. Also, note that a number of people (including me!) have pointed out that getting the memory sticks to fully seat is no easy task! I had to try a number of times before it finally "took," and since then, I've left well enough alone! See post #7 above for @Zltnnd's comment about this.

I was on the phone with apple so many times about my rebooting problem,I took out the OWC mods and re-installed them...still the same problem,trying different slots did not help either. The OWC mods alone still rebooted...so it had to be the OWC Mods were bad,will find out tomorrow when I get the exchanged mods in the mail. I was going to install the stock mods(4 gigs each} in slot 1 and 2 and the OWC mods (16gigs each) in slots 3 and 4. to see how that works. EDIT: when I was on the phone with the OWC tech he told me you can not mix the OWC MODS with stock..I find it odd because some are running both with no problems.

 

[camner]

I was on the phone with apple so many times about my rebooting problem,I took out the OWC mods and re-installed them...still the same problem,trying different slots did not help either. The OWC mods alone still rebooted...so it had to be the OWC Mods were bad,will find out tomorrow when I get the exchanged mods in the mail. I was going to install the stock mods(4 gigs each} in slot 1 and 2 and the OWC mods (16gigs each) in slots 3 and 4. to see how that works. EDIT: when I was on the phone with the OWC tech he told me you can not mix the OWC MODS with stock..I find it odd because some are running both with no problems.

I hope you are right and that the replacement OWS sticks work for you. I drew the same conclusion (that my OWC sticks were faulty) after many frustrating “insert, wouldn’t boot, remove, rinse and repeat” cycles. But, that turned out to be incorrect. When I followed Zltnnd’s advice (but it took 2 attempts), the OWC sticks worked for me. And, I have had zero issues since then. I got one of the early 2020 27” iMac models; I hope that after the poor experience of many early buyers with the finicky memory slots, Apple made the (minor?) modifications necessary to make it as easy to replace memory in this 2020 model as it was in earlier iMacs.

 

[tbird57]

I hope you are right and that the replacement OWS sticks work for you. I drew the same conclusion (that my OWC sticks were faulty) after many frustrating “insert, wouldn’t boot, remove, rinse and repeat” cycles. But, that turned out to be incorrect. When I followed Zltnnd’s advice (but it took 2 attempts), the OWC sticks worked for me. And, I have had zero issues since then. I got one of the early 2020 27” iMac models; I hope that after the poor experience of many early buyers with the finicky memory slots, Apple made the (minor?) modifications necessary to make it as easy to replace memory in this 2020 model as it was in earlier iMacs.

I will let you know the final results when I get them tomorrow.

 

[Mimosagracia]

I ordered the wrong ram at first (2x16gb) and it only ran at 2133Mhz (with and without the 8gb Apple ram), then I got 4x16gb of proper crucial ram and now it works perfectly at 2667Mhz. I've replaced the ram and fiddled around with it quite a few times but I've never had the machine not boot. One of the slots never really made a clicking sound like the rest did but it worked fine.

I've had a completely different sort of ram related ordeal, the ram door wouldn't fit in properly (one of the sides was sticking out) so I took it out and put it back and it stayed the same. So then when I pressed the button to release the door again 3 of the little hinges broke clean off the ram door. So now I'm stuck with a piece of paper on the hole to prevent dust from going in until my replacement door arrives. I think that's apples revenge for me not buying their ram Lol.

So yeah an unlucky day for me that was, although I just found it quite hilarious in the variety of problems I had with the ram replacement experience.

I ordered the wrong ram at first (2x16gb) and it only ran at 2133Mhz (with and without the 8gb Apple ram), then I got 4x16gb of proper crucial ram and now it works perfectly at 2667Mhz. I've replaced the ram and fiddled around with it quite a few times but I've never had the machine not boot. One of the slots never really made a clicking sound like the rest did but it worked fine.

I've had a completely different sort of ram related ordeal, the ram door wouldn't fit in properly (one of the sides was sticking out) so I took it out and put it back and it stayed the same. So then when I pressed the button to release the door again 3 of the little hinges broke clean off the ram door. So now I'm stuck with a piece of paper on the hole to prevent dust from going in until my replacement door arrives. I think that's apples revenge for me not buying their ram Lol.

So yeah an unlucky day for me that was, although I just found it quite hilarious in the variety of problems I had with the ram replacement experience.

I had thesame problem with the RAM slot door. I thought the reason why my Mac doesn't turn on is because of that. One of the pin got knocked out. And it wont fit perfectly. It is slightly open.

I tried to add another OWC RAM 32gb 2666mhz mix with the original 2 4gb RAM. I did the pairing of slot but as soon as I have it done, my Mac wont no longer work. It doesnt turn on. Its been 3 days now.