64GB (4x16GB) DDR4 2666MHz Memory Upgrade for 27in iMac

In this review the 64GB (4x16GB) DDR4 2666 MHz memory kit is evaluated for owners of the 2019 and 2020 27in iMac with Retina 5K displays who need more RAM for demanding work. The bottom line: this kit provides a straightforward and cost-effective way to boost multitasking and memory-heavy applications, especially for video editing, large image files, and virtual machines. The reviewer found the modules reliable in routine use and appreciated the clear compatibility notes for model IDs and factory configurations.

Key Features

• Capacity and configuration: Four 16GB SODIMM modules combine to deliver 64GB total, enabling heavier multitasking and larger in-memory projects than stock configurations.
• Memory speed: DDR4 2666 MHz operation matches the supported speed for the target iMac models so the modules run at expected system rates.
• Module type: 260-pin dual rank Unbuffered SODIMM modules fit the 27in iMac expansion slots for a direct, user-accessible upgrade path.
• Compatibility guidance: The listing specifies compatibility with 2019 model ID 19,1 and 2020 model IDs 20,1 and 20,2, reducing guesswork when matching to specific iMac SKUs.
• Warranty support: A limited lifetime warranty from the brand covers defective memory replacements under like-for-like specifications.

Who It's For

This kit is aimed at creative professionals, power users, and anyone running memory-intensive tasks on a compatible 27in iMac who needs a reliable 64GB configuration without sourcing individual modules. It is well suited for video editors, photographers using large files, software developers running multiple VMs, and anyone who outgrew 32GB.

Those with different iMac models, machines that require ECC or server memory, or users who cannot open their iMac should look elsewhere. Also, shoppers who insist on first-party OEM memory from specific manufacturers may prefer branded original modules.

Pros & Cons

Pros

• Good value for moving a compatible 27in iMac to 64GB without complex configuration.
• Reported by users to be stable and to run at full speed on supported machines.
• Every module is tested by the manufacturer and backed by a limited lifetime warranty for defects.

Cons

• Warranty covers only the brand memory and excludes physical or cosmetic damage, and does not cover major OEM-branded modules.
• Compatibility is limited to specific 2019 and 2020 27in iMac model IDs, so verification before purchase is required.

Specifications

Our Verdict

The 64GB 4x16GB DDR4 2666 MHz SODIMM kit is a practical, cost-effective upgrade for compatible 27in iMac owners who need more RAM for creative or professional workflows. It delivers expected speed and stability when installed in the specified 2019 and 2020 iMac models and offers manufacturer testing and a limited lifetime warranty, making it a sensible choice for users prioritizing capacity and reliable operation.

Frequently Asked Questions

Will this kit work in my 27in iMac?
Check your iMac model ID: the kit lists compatibility with 2019 model ID 19,1 and 2020 model IDs 20,1 and 20,2 for supported CPU variants.

Does the warranty cover installation damage?
The limited lifetime warranty covers defective memory replacements but excludes physical or cosmetic damage and only applies to the brand memory specified.

Will the modules run at full 2666 MHz?
On supported iMac models the modules run at the system-supported 2666 MHz rate; customers reported full-speed operation when correctly installed.