imac 2020 27inch compatible ram

You really need to be super careful about getting the exact type of RAM required. Per this KB article, the 2020 27" iMac requires:

iMac (Retina 5K, 27-inch, 2020) memory specifications for iMac (Retina 5K, 27-inch, 2020),

Memory specifications

This iMac model features Synchronous Dynamic Random-Access Memory (SDRAM) slots on the rear of the computer near the vents with these memory specifications:

Number of memory slots4Base memory8GB (2 x 4GB DIMMs)Maximum memory128GB (4 x 32GB DIMMs)

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

• • PC4-21333
  • Unbuffered
  • Nonparity
  • 260-pin
  • 2666MHz DDR4 SDRAM

Instructions here regarding how to install memory in this model.

There are a number of excellent third party vendors, with detailed videos on how to do it and other detailed information.

Good luck!

-- JDee

LIGHTZOFF wrote:

I have also realised that the required Apple ram specs for upgrade are PC4-21333, however, will PC4-21300 still work as I couldn’t find any ram that was PC4-21333? This thread says it will work, but wanted to confirm: https://discussions.apple.com/thread/251408870

As the link states, they are one and the same.

Lastly, I heard that I cannot add additional ram on top of the 8gb that is included with my Mac, is that true?

Not true. See: Install memory in an iMac - Apple Support

It definitely helps! Thank you.

I'm purchasing the same memory (just 2x 32GB in kit).

I want to clear up a couple of things though:

1. AFAIK mixing Apple with any memory (Crucial's "For Mac" as well) will reduce RAM speed to 2133.
2. The reason why it works in the last configuration (and should in theory work in the second as well) is because you're disabling Dual Channel. You get faster speed, but not dual channel
3. The reason to purchase kit (and why it sometimes is a tiny bit more expensive) is because they are paired. This is to optimize dual channel compatibility. So if you purchase 2x kits, you should make sure each kit goes in their separate dual channel location (1+3 & 2+4).
4. PC4-21333 vs PC4-21300 is the exact same thing. It's just a matter of rounding the number (three digits vs five).
5. If you remove the original Apple RAM and put the Crucial RAM where the Apple RAM was originally, you should get both 2667MHz speed AND dual channel.

Please test number 5 if possible.

If you do the menu : About This Mac : Memory, that panel will inform you what speed of RAM each slot will accept. The option-key + menu : System Information : Memory will also tell you what speed of RAM is installed.

so crucial tech support vehemently say that CT16G4SFD8266 is not compatible and that its speed is PC4-25600 and PC4-21300 (their stupid website has both the speeds listed). Oh well!!!! any issues you have seen so far?

Not a chance!!!!! Only purchase iMac RAM from Macsales.com or direct drop Crucial.com. iMacs are very sensitive to using quality RAM and both vendors supply just that, sell for reasonable prices and offer lifetime warranties on RAM. In short there is no reason to buy from anyone else.

Just to clarify things for you, PC4-21333 and PC4-21300 modules are identical. Some companies choose to round the spec to three whole numbers. Technically, they should be listed as PC4-21333.33…

👍

Would you guys buy this Nemix ram from Newegg for the new iMac (2020)?

Thank you. Have you looked at CT16G4SFD8266 vs CT16G4S266M)

No and as I stated only purchase from Crucial.com or Macsales.com, not Amazon, not NewEgg not anyone else.