iMac (2020) showing RAM running at 2133MHz, but tech specs say 2666?

[RoboCop001]

Hi everyone,

Just got my iMac set up and I noticed the RAM is running at 2133MHz instead of the rated 2666MHz on the tech specs page. I also purchased OWC RAM which is rated at 2666MHz. But system report shows them all running at 2133.

I just triple checked the RAM I bought and the tech specs page and they all say 2666MHz.

The RAM installed is: 4GB, 4GB, 16GB, 16GB. The two 4GB are the ones that came with it.

Any idea what's going on? Could it be because they're not all the same size?

 

[PBG4 Dude]

There’s another RAM thread here that goes into this in more detail. Basically, you have 3 options. 1) keep the current setup, and deal with lower RAM speed but keep dual-channel active. 2) slot Apple RAM in slots 1-2 or 3-4 and put 3rd party RAM in the two empty slots. This will bring you back up to 2666 speed but will eliminate dual-channel from being active. 3) only install 3rd party RAM, lose 8GB space, but get both 2666 and dual-channel.

 

[pldelisle]

Please refer to this thread : https://forums.macrumors.com/threads/memory-upgrade-troubleshooting-in-2020-27-inch-imacs.2249254/

 

[RoboCop001]

There’s another RAM thread here that goes into this in more detail. Basically, you have 3 options. 1) keep the current setup, and deal with lower RAM speed but keep dual-channel active. 2) slot Apple RAM in slots 1-2 or 3-4 and put 3rd party RAM in the two empty slots. This will bring you back up to 2666 speed but will eliminate dual-channel from being active. 3) only install 3rd party RAM, lose 8GB space, but get both 2666 and dual-channel.

Please refer to this thread : https://forums.macrumors.com/threads/memory-upgrade-troubleshooting-in-2020-27-inch-imacs.2249254/

Thanks! I checked out that thread. Interesting. Good to know!

 

[Luca Allard]

Thanks! I checked out that thread. Interesting. Good to know!

THANKS! That did the trick. My 2020 iMac 27" was ordered with 16GB of ram at 2667MHZ. I bought OWC 16 GB(2X8) and put it in on alternating slots. It came back as 2133MHz. When I put the 2 Apple ram sticks in slots 1 & 2 then put the OWC sticks in slots 3 & 4, it now says 2667MHz !!!!!

 

[Schnauzer World]

THANKS! That did the trick. My 2020 iMac 27" was ordered with 16GB of ram at 2667MHZ. I bought OWC 16 GB(2X8) and put it in on alternating slots. It came back as 2133MHz. When I put the 2 Apple ram sticks in slots 1 & 2 then put the OWC sticks in slots 3 & 4, it now says 2667MHz !!!!!

The OWC RAM right now for 2x16 is $119, Crucial is $159. Is the Crucial worth $40 more?

 

[pldelisle]

The OWC RAM right now for 2x16 is $119, Crucial is $159. Is the Crucial worth $40 more?

Totally.

 

[Benz63amg]

THANKS! That did the trick. My 2020 iMac 27" was ordered with 16GB of ram at 2667MHZ. I bought OWC 16 GB(2X8) and put it in on alternating slots. It came back as 2133MHz. When I put the 2 Apple ram sticks in slots 1 & 2 then put the OWC sticks in slots 3 & 4, it now says 2667MHz !!!!!

Yes but is it running in dual channel Mode? Only way to run in dual channel mode at full speed is to upgrade ALL ram modules with third party modules in the 2020 iMacs

 

[AZREOSpecialist]

Yes but is it running in dual channel Mode? Only way to run in dual channel mode at full speed is to upgrade ALL ram modules with third party modules in the 2020 iMacs

No. The only way to run in dual channel mode at full speed is to make sure all RAM modules are identical. Big difference.

 

[Benz63amg]

No. The only way to run in dual channel mode at full speed is to make sure all RAM modules are identical. Big difference.

i should have better rephrased my sentence, Thanks for clarifying. Why is the 2020 iMac so picky with the RAM? i easily used the existing 8GB original apple Ram sticks along with 2 x 16gb Ram sticks from OWC and i get dual channel at full speed.

 

[pldelisle]

i easily used the existing 8GB original apple Ram sticks along with 2 x 16gb Ram sticks from OWC and i get dual channel at full speed.

Impossible in 2020 iMac.

 

[Benz63amg]

Impossible in 2020 iMac.

So all 4 Ram sticks need to be the same exact type of Ram stick such as 4 x 16GB identical OWC Ram sticks, correct?

 

[pldelisle]

So all 4 Ram sticks need to be the same exact type of Ram stick such as 4 x 16GB identical OWC Ram sticks, correct?

Even at OWC they have both Micron and Hynix DRAM chips. There is now way to know which you are going to get. Only Crucial has a single supplier which is Micron. This is the only manufacturer that is 100% certified compatible and 100% sure that will use the same ICs in the future.