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Four green DDR4 SODIMM sticks, 260-pin, no heat spreaders

NEMIX RAM

NEMIX RAM 64GB (4x16GB) DDR4 2666 CL19 260-pin SODIMM memory upgrade for Apple iMac 27" 2020

SKU CH-JYRS-TDCBK

A 64 GB kit of four 16 GB DDR4 2666 CL19 SODIMM modules built for the 27-inch 2020 iMac

  • Total capacity64 GB (4 × 16 GB)
  • Rated speedDDR4 2666 (PC4 21300)
  • ChipsetMajor OEM Samsung, Micron, Hynix
  • CAS latencyCL19
  • Buffer typeUnbuffered
  • Rated voltage1.2 V

Capacity 64GB 4X16GB

  • 64 GB kit lets iMac 27″ 2020 handle heavy multitasking
  • DDR4 2666 CL19 matches factory speed and timing exactly
  • Four 16 GB SODIMMs fill every slot for maximum capacity
  • 2 V low-voltage modules run cool inside the all-in-one chassis
  • Major-brand Samsung Micron Hynix chips ensure rock-solid stability

64GB DDR4 2666 kit for 2020 iMac

This 64GB kit contains four 16GB DDR4 2666 SODIMM modules built for the 27-inch iMac with Retina 5K display released in 2020. It matches the factory PC4-21300 specification and uses the 260-pin form factor required by that all-in-one desktop. Non-ECC unbuffered operation suits the consumer macOS memory controller.

Sustained workload stability

Modules are stress-tested under load using major OEM chips from Samsung Micron or Hynix to maintain error-free operation during long rendering sessions or virtual-machine workloads. The CL19 latency and 1.20V voltage remain steady without thermal throttling because the iMac's internal airflow passes over the bare PCB. Dual-rank 2Rx8 organisation keeps bandwidth consistent across all four slots.

No heat spreader compact layout

The absence of a heat spreader lets the modules fit the tight SO-DIMM clearance behind the iMac display panel. Standard 260-pin gold-edge connectors seat directly into the factory slots without adapters or shims. A four-module population fills every available slot so no further expansion is possible inside this chassis.

How it compares

Measured against everything we stock in Model-Specific Memory Upgrades, at today’s prices. Recalculated every night.

Price $274.99
Cheaper than about 55% of the 21,161 comparable items (median $397.99).
Total capacity 64 GB (4 × 16 GB)
Higher than about 60% of the 20,941 comparable items (median 32 GB).
Price per GB $4.30 per GB
Cheaper than about 83% of the 20,941 comparable items (median $8.19 per GB).

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Specifications

Product
Brand nameNEMIX RAM
Product lineApple iMac/Mac Mini Compatible Series Memory
Model nameApple DDR4 2666 MHz Non-ECC Unbuffered SODIMM
Part numberMS21300-628K4
Total capacity64 GB (4 × 16 GB)
Product type260-Pin DDR4 SODIMM
Performance
Rated speedDDR4 2666 (PC4 21300)
Processor
ChipsetMajor OEM Samsung, Micron, Hynix
Memory
CAS latencyCL19
ECC supportNo
Buffer typeUnbuffered
Heat spreaderNo
Memory rank2Rx8
Power
Rated voltage1.2 V
Compatibility
Compatible systemsApple
In the box
Included items64 GB (4 × 16 GB) DDR4 2666 MHz PC4-21300 2Rx8 1.2 V CL19 260-PIN Non-ECC Unbuffered SODIMM KIT

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Questions about this item

How much power does the 64GB DDR4 2666 CL19 kit draw at 1.20V during sustained workloads?

Each 16GB module runs at 1.20V DDR4 standard voltage; total draw depends on system load but stays within normal SODIMM limits for the iMac 27" 2020.

Does the 260-pin SODIMM kit require any tools or extra parts to install in the iMac 27" 2020?

No extra parts are needed; the 4x16GB modules fit the SO-DIMM slots directly, though Apple recommends a soft cloth and anti-static precautions during installation.

Will the 2Rx8 CL19 modules work alongside the original 8GB or 16GB sticks already in the iMac 27" 2020?

The kit is validated for the iMac 20,1 and iMac 20,2; mixing ranks and latencies is not recommended, so replace all slots with this matched 64GB set for stability.

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