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Two green 204-pin DDR3 SO-DIMM sticks, no heat spreaders, 16GB kit

Computer Memory Solutions

Computer Memory Solutions 16GB (2x8GB) DDR3 1333 SO-DIMM iMac 21.5 Mid-2011

SKU CH-EYXH-BHQ9Y

A 16 GB dual-channel DDR3 1333 SO-DIMM kit built for the 21.5-inch 2011 iMac with a 2.7 GHz Core i5

  • Total capacity16 GB (2 × 8 GB)
  • Rated speedDDR3 1333 (PC3 10600)
  • ChipsetMajor Brand Chipset
  • CAS latencyCL9
  • Memory timings9-9-9
  • Rated voltage1.5 V
  • 16 GB kit upgrades the 21.5-inch Mid-2011 iMac to its 32 GB maximum
  • Two 8 GB modules populate two of the four SO-DIMM slots
  • DDR3 1333 MHz CL9 timing matches the factory specification
  • 5 V unbuffered non-ECC design installs without configuration
  • 204-pin SO-DIMM form factor fits the iMac memory compartment

Compatible iMac memory kit

This 16 GB kit contains two 8 GB DDR3 SO-DIMM modules rated at 1333 MHz. It is built for the Apple iMac 21.5-inch Mid-2011 model with a 2.7 GHz Core i5 processor. The unbuffered, non-ECC sticks run at 1.5 V with CL9 timings.

Upgrading from the factory 4 GB

The iMac shipped with 4 GB across two slots; this kit fills all four sockets and reaches the 16 GB ceiling for this configuration. The jump is worthwhile when macOS, creative apps or virtual machines regularly exhaust the original memory and cause swapping.

Check your exact model identifier

Confirm the machine shows iMac12,1 and part number MC812LL/A in About This Mac before ordering. The system supports a maximum of 32 GB across four slots, so this 16 GB kit leaves room for a future matched pair if needed.

How it compares

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

Price $41.99
Cheaper than about 80% of the 21,161 comparable items (median $397.99).
Total capacity 16 GB (2 × 8 GB)
Lower than about 70% of the 20,941 comparable items (median 32 GB).
Price per GB $2.62 per GB
Cheaper than about 91% of the 20,941 comparable items (median $8.19 per GB).

New to this? Buying memory and SSDs with crypto — what to check, what it costs to pay, and what is never asked for.

Specifications

Product
Brand nameComputer Memory Solutions
Model nameCM10246410600SODRH
Total capacity16 GB (2 × 8 GB)
Product type204-Pin DDR3 SO-DIMM
Performance
Rated speedDDR3 1333 (PC3 10600)
Processor
ChipsetMajor Brand Chipset
Memory
CAS latencyCL9
Memory timings9-9-9
ECC supportNo
Buffer typeUnbuffered
Memory rank2Rx8
Heat spreaderNo
Power
Rated voltage1.5 V
Compatibility
Compatible systemsApple Imac "Core I5 in 2.7 21.5 in (Mid-2011)
In the box
Included items2 Memory RAM Sticks

Questions about this item

Does this 204-pin DDR3 SO-DIMM kit fit the four memory slots in the 21.5-inch Mid-2011 iMac?

Yes. The kit provides two 8 GB modules for the four SO-DIMM slots in the 21.5-inch Mid-2011 iMac, bringing total memory to 16 GB against a 32 GB maximum.

What is the correct way to seat these unbuffered CL9 modules so the iMac recognises the full 16 GB?

Power off and unplug the iMac, remove the memory access door, insert each module at a slight angle until the gold contacts are hidden, then press down firmly until both side clips click.

When should the two 8 GB sticks be replaced if the iMac starts showing memory errors?

Replace them if Apple Diagnostics reports a memory failure or the system kernel-panics repeatedly; the modules carry a limited lifetime warranty from Computer Memory Solutions.

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