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Crucial CT8G3S1339M 8GB DDR3 1333MHz SODIMM Mac Memory — main product image
Crucial CT8G3S1339M 8GB DDR3 1333MHz SODIMM Mac Memory
Crucial CT8G3S1339M 8GB DDR3 1333MHz SODIMM Mac Memory
Crucial CT8G3S1339M 8GB DDR3 1333MHz SODIMM Mac Memory
Crucial CT8G3S1339M 8GB DDR3 1333MHz SODIMM Mac Memory
Crucial CT8G3S1339M 8GB DDR3 1333MHz SODIMM Mac Memory
Crucial CT8G3S1339M 8GB DDR3 1333MHz SODIMM Mac Memory
Crucial

Crucial CT8G3S1339M 8GB DDR3 1333MHz SODIMM Mac Memory

★★★★★4.7 (3059 reviews)

Eight gigabytes of DDR3L dual-voltage SODIMM memory at 1333MHz unlocks the full multi-tasking potential of DDR3-era MacBook Pro and iMac systems in a single drop-in module.

$29.49*$29.71Save 0%
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*Price sourced from Amazon.com. Last updated:Jun 04, 2026.Price and availability are subject to change.

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Overview

The Crucial CT8G3S1339M is an 8GB DDR3/DDR3L SODIMM running at 1333MT/s (PC3-10600) with CL9 latency on a 204-pin form factor, designed to upgrade DDR3-era Mac systems. The dual-voltage design — operating at either 1.35V (DDR3L) or 1.5V (DDR3) — is the key specification that makes this module broadly compatible across multiple generations of Apple laptops and desktops without requiring buyers to determine whether their specific model uses standard or low-voltage DDR3. At 8GB single-module capacity, it can double the installed RAM of a typical 4GB MacBook Pro configuration in a single installation, or serve as one half of a 16GB dual-module upgrade in systems with two accessible SODIMM slots.

For owners of DDR3-era MacBook Pro (2010–2011), Mac mini, and compatible iMac configurations, a RAM upgrade is typically the most cost-effective performance intervention available. macOS and browser workloads regularly exceed 4GB under normal multi-application use, forcing the system to write active memory to disk swap — a slow, audible operation that degrades responsiveness significantly. Moving to 8GB or 16GB eliminates most swap activity under typical workloads, restoring the snappy feel these machines had when current. The CT8G3S1339M installs without tools on MacBook Pro models with accessible SODIMM bays, and Crucial's lifetime warranty provides long-term protection on a component going into hardware that may be years from replacement.

Key Features

204-pin SODIMM

DDR3-1333

Specifications

Capacity
8GB
Type
DDR3 / DDR3L
Speed
1333 MT/s (PC3-10600)
Latency
CL9
Voltage
1.35V (DDR3L) / 1.5V (DDR3) dual voltage
Pins
204-pin
Form Factor
SODIMM
Compatibility
Select Mac systems (verify via Crucial compatibility tool)

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Pros & Cons

👍 Pros

  • 8GB single-module capacity fills one slot completely, leaving the second slot free for a matched pair and dual-channel configuration
  • 8GB single-module capacity allows a meaningful RAM upgrade in DDR3 Mac models without requiring a matched pair — install one to double from 4GB
  • Dual-voltage DDR3/DDR3L design operates at 1.35V or 1.5V, providing compatibility across the full range of DDR3-era Mac platforms without specification lookup
  • DDR3L 1.35V low-voltage operation reduces power draw and thermal output — a meaningful benefit in thermally constrained MacBook Pro enclosures
  • 204-pin SODIMM form factor matches the physical specification of compatible Mac laptops and mini desktops exactly
  • 1333MT/s at CL9 timing is within the factory spec for DDR3-era MacBook Pro models — no overprovisioning risk or SPD conflicts during Mac startup
  • 204-pin SODIMM form factor is the standard laptop memory interface for all DDR3 MacBook Pro and Mac mini models with upgradeable RAM
  • PC3-10600 (1333 MT/s) speed rating meets Apple's certified memory specification for supported systems without requiring any BIOS adjustment
  • CL9 latency delivers consistent, predictable timing within the DDR3-1333 standard across all supported operating conditions
  • Crucial's lifetime warranty and 100% testing policy give confidence in a component being installed in older hardware where compatibility issues are otherwise common

👎 Cons

  • DDR3-1333 is a legacy memory standard — this module is incompatible with any Mac released after Apple transitioned to DDR4 or soldered non-upgradeable RAM
  • 1333MT/s DDR3 is the specified speed for these Mac models but is a platform ceiling — this module cannot push performance beyond what the Mac's memory controller supports
  • Single-module operation at 8GB will not achieve full dual-channel bandwidth on Mac models with two SODIMM slots — pairing with an identical second module maximizes bandwidth
  • Mac firmware enforces strict memory speed limits and does not allow overclocking beyond the 1333 MT/s rated speed of this module
  • No XMP or performance profiles are present — the module runs only at its factory-rated DDR3-1333 specification with no headroom for tuning
  • 204-pin DDR3 SODIMMs are physically incompatible with DDR4 SODIMM slots — not transferable to newer Mac models with DDR4 or LPDDR4 memory
  • CL9 latency, while solid for DDR3-1333, is the standard timing — no performance headroom beyond rated spec is available on a non-XMP SODIMM in a Mac
  • Single-module installation runs in single-channel mode; realizing full dual-channel bandwidth requires purchasing and installing a second matched module
  • Compatibility must be confirmed against Crucial's Mac-specific lookup tool — ordering without verification risks receiving a physically correct but firmware-incompatible module
  • These DDR3 Mac platforms themselves are aging hardware; the RAM upgrade extends usable life but does not address CPU or GPU performance ceilings

Frequently Asked Questions

Compatibility is model-specific and must be verified before purchasing. This module targets Macs that shipped with user-upgradeable DDR3 or DDR3L SO-DIMMs — primarily MacBook Pro models from 2011 through 2015 and Mac mini models from 2011 through 2014. Crucial's online compatibility checker, which requires only your Mac's model identifier, is the definitive resource for confirming fit before you order.
This is a 204-pin DDR3/DDR3L SODIMM rated at 1333MT/s (PC3-10600), which corresponds to the memory specification used in several MacBook Pro (mid-2010 through late-2011), MacBook (late-2009 and 2010), Mac mini, and iMac configurations. Crucial's online compatibility tool at crucial.com can confirm compatibility by entering your Mac's specific model identifier or serial number — always verify before purchasing.
DDR3L means low-voltage DDR3 — it runs at 1.35V instead of the standard DDR3 1.5V. This module is dual-voltage: it operates at either 1.35V or 1.5V depending on what the motherboard requests. That dual-voltage flexibility ensures compatibility with both standard DDR3 and DDR3L Mac platforms without requiring you to identify which specification your specific model needs.
The 204-pin DDR3 SODIMM form factor and DDR3L dual-voltage design are not exclusive to Mac systems — any DDR3 laptop that accepts 1333 MT/s SO-DIMMs at 1.35V or 1.5V can technically use this module. However, Crucial certifies the CT8G3S1339M specifically against Mac system firmware, and compatibility with non-Mac systems should be verified independently against your device's memory specification.
Some Macs require standard 1.5V DDR3 signaling, while others support the lower-power DDR3L standard at 1.35V. This module operates at both voltages — the memory controller in your Mac negotiates the correct operating voltage automatically at boot. In practice, the 1.35V DDR3L mode reduces power draw and heat generation, which benefits thermally constrained MacBook Pros where memory heat is a real concern under sustained load.
Yes — on Mac models running macOS or OS X with 4GB installed, the RAM is frequently the primary bottleneck under normal use. Adding 8GB (or going to 16GB with two 8GB modules) dramatically reduces disk swapping and significantly improves responsiveness when running multiple applications, browser tabs, or creative software. For these machines, RAM is typically the single most impactful upgrade available.
The late-2011 MacBook Pro (the last model with user-accessible RAM) officially supports up to 8GB, but many owners have successfully run 16GB (2×8GB) despite Apple's official spec. The mid-2010 and early models officially cap at 8GB. Verify your specific model's realistic maximum before purchasing multiple modules.
Apple explicitly allows user-installed RAM upgrades on Mac models with accessible memory slots — the product manuals for compatible models include RAM installation instructions. Adding third-party RAM does not void the overall warranty. Note that post-2015 MacBooks with soldered memory have no user-accessible slots; this module is irrelevant for those systems.
Yes. A single CT8G3S1339M installed in one slot operates in single-channel mode, utilizing only half the theoretical memory bandwidth. Installing a matched pair — one in each slot — enables dual-channel operation, which provides up to a 30% increase in memory bandwidth on compatible Mac systems. For memory-intensive workflows, the matched pair configuration is worth the additional cost.
Yes — a 204-pin DDR3/DDR3L SODIMM at 1333MT/s is a standard laptop memory format. This module is not Mac-exclusive; any laptop or compact desktop that accepts 204-pin DDR3 or DDR3L SODIMMs at 1333MHz is compatible. Crucial markets it specifically for Mac use, but the module itself is architecturally standard.

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