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I bought this RAM for 2020 iMac but it doesn't fit

L

levmc

macrumors 6502a
Original poster
Jan 18, 2019
687
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I bought this one (attracted by higher speed than 2666):
www.amazon.com

Crucial RAM 64GB Kit (2x32GB) DDR5 4800MHz CL40 Laptop Memory CT2K32G48C40S5

CT2K32G48C40S5 is the Crucial 64GB kit consisting of (2) 32GB laptop modules that operate at the speed of 4800MHz and has a CAS Latency of 40. It is an SODIMM and conforms to the industry standard DDR5 SODIMM layout of 262 pins. It is compatible with systems that can take DDR5-4800 SODIMM memory.
www.amazon.com
but realized that it didn't fit in iMac.

I'm going to return this, and I'm guessing I need to buy a SODIMM RAM for it to work on iMac?
Would this be the best choice? https://www.amazon.com/OWC-2666MHz-PC4-21300-OWC2666DDR4S64P-macmini18/dp/B07PTRZSHB/ref=sr_1_7_sspa?crid=2QE4HV4HWLI3H&keywords=2x32gb+imac+ram&qid=1684251445&s=electronics&sprefix=2x32gb+imac+ram,electronics,106&sr=1-7-spons&ufe=app_do:amzn1.fos.f5122f16-c3e8-4386-bf32-63e904010ad0&smid=A2W0TEJ3MK1XP5&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFDSVQ4UFc0RERRQVgmZW5jcnlwdGVkSWQ9QTAxNDUzNjkyNjMyVkhDMldCUkxNJmVuY3J5cHRlZEFkSWQ9QTA0Nzk1MDMzSDFBT1hXNVZHVDk5JndpZGdldE5hbWU9c3BfbXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1

Does anyone have any other suggestion?
 
As an Amazon Associate we earn from qualifying purchases.
Are there any RAM models for iMac that are faster than 2666mhz by chance?
 
Last edited:
levmc said:
Are there any RAM models for iMac that are faster than 2666mhz by chance?
Click to expand...
Depending on what CPU your iMac has it seems like it might work with faster RAM. Specifically the Core i7/i9 (10700/10910) support 2933 MHz according to Intel, but I have no idea if the iMac as a whole supports it.
 
curnalpanic said:
Depending on what CPU your iMac has it seems like it might work with faster RAM. Specifically the Core i7/i9 (10700/10910) support 2933 MHz according to Intel, but I have no idea if the iMac as a whole supports it.
Click to expand...
I do have i7 (2020 iMac)

Would this one work? Would it be faster than the one in my original post?
www.amazon.com

Crucial RAM 64GB Kit (2x32GB) DDR4 3200MHz CL22 (or 2933MHz or 2666MHz) Laptop Memory CT2K32G4SFD832A

CT16G4SFD824A is a 16GB DDR4 Notebook module that operates at speeds up to 2400 MT/s and has a CL17 latency. It is an Buffered SODIMM. It conforms to the industry standard DDR4 SODIMM layout of 260 pins and is compatible with systems that take DDR4 2400MT/s SODIMM memory.
www.amazon.com
 
As an Amazon Associate we earn from qualifying purchases.
levmc said:
Would this one work?
Click to expand...

Looks like any RAM faster than 2666 MHz is wasted money in an iMac. (Scroll to the bottom of this iFixit thread).
www.ifixit.com

SOLVED: What is best Ram (16x4) for iMac 2020? - iMac Intel 27" Retina 5K Display 2020

The issue you face is the number of slots (4) and the amount of RAM your system could support (max) Using two slots we can use: (1) 4GB SO-DIMM’s getting to a total of 8GB (2) 8GB SO-DIMM’s getting to a total of 16GB (3) 16GB SO-DIMM’s getting to a total of 32GB (4) 32GB SO-DIMM’s getting to...
www.ifixit.com www.ifixit.com

Also, are you planning to keep your existing sticks in there? If so they all need to be the same speed.
 
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levmc said:
I do have i7 (2020 iMac)

Would this one work? Would it be faster than the one in my original post?
www.amazon.com

Crucial RAM 64GB Kit (2x32GB) DDR4 3200MHz CL22 (or 2933MHz or 2666MHz) Laptop Memory CT2K32G4SFD832A

CT16G4SFD824A is a 16GB DDR4 Notebook module that operates at speeds up to 2400 MT/s and has a CL17 latency. It is an Buffered SODIMM. It conforms to the industry standard DDR4 SODIMM layout of 260 pins and is compatible with systems that take DDR4 2400MT/s SODIMM memory.
www.amazon.com
Click to expand...
I don't think that will work. You can see directly on Crucial.com the compatible DIMMS for your machine specifically.
www.crucial.com

Apple iMac (Retina 5K, 27-inch, 2020) iMac20,2 | Memory RAM & SSD Upgrades | Crucial.com

Crucial Memory and SSD upgrades - 100% Compatibility Guaranteed for Apple iMac (Retina 5K, 27-inch, 2020) iMac20,2 - FREE US Delivery.
www.crucial.com www.crucial.com
 
As an Amazon Associate we earn from qualifying purchases.
curnalpanic said:
Looks like any RAM faster than 2666 MHz is wasted money in an iMac. (Scroll to the bottom of this iFixit thread).
www.ifixit.com

SOLVED: What is best Ram (16x4) for iMac 2020? - iMac Intel 27" Retina 5K Display 2020

The issue you face is the number of slots (4) and the amount of RAM your system could support (max) Using two slots we can use: (1) 4GB SO-DIMM’s getting to a total of 8GB (2) 8GB SO-DIMM’s getting to a total of 16GB (3) 16GB SO-DIMM’s getting to a total of 32GB (4) 32GB SO-DIMM’s getting to...
www.ifixit.com www.ifixit.com

Also, are you planning to keep your existing sticks in there? If so they all need to be the same speed.
Click to expand...
I saw this video:

The video says if you want a higher speed, as long as you put the existing 2 lower speed RAMs on the first 2 slots, the iMac will recognize the higher speed of the 3rd and 4th slots.
 
At least in my experience, that video, if it actually says what you posted, is a bit misleading.
I would correct that to state: the iMac may recognize a higher speed pair (which has to also meet the other specs needed for RAM in your iMac) in the 3rd and 4th slots.
Doesn't always work, so you would need to try that yourself. If it does work (reporting higher speed), then that's a Good Thing™. If not, you would then continue by testing another manufacturer's RAM sticks.
Yes, you are correct, to a point. All DDR4 should work (at least up to 32GB sticks), but the reality shows that most any Mac can still be finicky about how RAM is used, and which RAM actually works properly.
Bottom line (maybe this is a bit simplistic): the memory that works when you try it in your Mac, is the best memory to use. Getting full theoretical clock speed is perhaps a bonus at that point.
 
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RAM transfer speed is a relatively minor factor in overall computer speed. For example, a 20% increase in RAM speed will likely result in about 5% improvement in a benchmark score. (My experience). Might be something to consider when deciding how much expense and effort to spend doing so.
 
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Anyways, I did buy this I mentioned above:

www.amazon.com

Crucial RAM 64GB Kit (2x32GB) DDR4 3200MHz CL22 (or 2933MHz or 2666MHz) Laptop Memory CT2K32G4SFD832A

CT16G4SFD824A is a 16GB DDR4 Notebook module that operates at speeds up to 2400 MT/s and has a CL17 latency. It is an Buffered SODIMM. It conforms to the industry standard DDR4 SODIMM layout of 260 pins and is compatible with systems that take DDR4 2400MT/s SODIMM memory.
www.amazon.com

And even though it does work, it downclocked to 2667, not 3200 as I hoped.
 
As an Amazon Associate we earn from qualifying purchases.
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