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Crucial

Crucial CT3309273 8GB DDR3 RAM Kit for Apple iMac/MacBook Pro

★★★★★4.5 (267 reviews)

A Crucial-certified 8GB DDR3-1333 kit that eliminates the RAM ceiling holding back your older Apple iMac or MacBook Pro.

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Overview

The Crucial CT3309273 is an 8GB DDR3 upgrade kit — two 4GB SO-DIMM modules running at 1333MHz (PC3-10600) — engineered specifically for Apple iMac and MacBook Pro systems that shipped with DDR3 memory slots. The specification is precise by design: DDR3-1333 is the native clock speed Apple's memory controllers in these systems were validated to run, and Crucial's Mac-approval process ensures the modules meet Apple's timing and signal integrity requirements. What 8GB of dual-channel DDR3 actually solves in practice is the memory pressure that accumulates on older Macs running modern macOS — where the operating system baseline, browser, and a handful of applications together consume enough RAM to push a 4GB system into disk-based swap, introducing the page-out latency that manifests as sluggishness and spinning wait cursors.

This kit is purpose-built for a specific install base: aging but capable Apple hardware where the CPU and storage aren't the bottleneck, but RAM capacity is artificially limiting performance. It's the right upgrade for a MacBook Pro or iMac that's running slowly not because the processor is obsolete, but because the system is constantly borrowing disk space to compensate for insufficient physical memory. Installation is physically straightforward on most target models, and macOS recognizes the additional capacity immediately at boot with no software configuration required. The lifetime warranty from Crucial provides coverage that outlasts the useful life of the system in most cases — a low-risk upgrade for extending the productive life of Apple hardware that would otherwise feel obsolete before its hardware is genuinely worn out.

Key Features

DDR3-1333Mhz

PC3-10600

Mac Approved

Lifetime Warranty

Specifications

RAM Capacity
8GB
RAM Type
DDR3
Speed
1333Mhz
Module Type
PC3-10600
Compatibility
Apple iMac/MacBook Pro, Mac Approved
Warranty
Lifetime Warranty

Pros & Cons

👍 Pros

  • The 2x4GB dual-channel configuration runs both modules simultaneously, providing the full bandwidth benefit of the dual-channel memory bus in compatible Apple iMac and MacBook Pro configurations.
  • DDR3-1333MHz (PC3-10600) matches Apple's native specification for supported systems exactly — no frequency downclocking, no compatibility guesswork.
  • Crucial's Mac-approved validation process means the modules are tested against Apple's ECC and timing requirements, reducing the risk of kernel panics or instability from timing mismatches that generic DRAM can introduce.
  • The lifetime warranty provides long-term coverage on a component that is expected to outlast the system it's installed in — rare for a consumable upgrade at this price point.
  • At 8GB total capacity, this kit addresses the primary performance bottleneck on older Apple systems running current or recent macOS versions, where the OS itself has grown to consume more baseline RAM than earlier releases.

👎 Cons

  • DDR3-1333MHz is a legacy standard — this kit is not forward-compatible with any current Apple hardware or DDR4/DDR5 systems, limiting its application to a narrowing pool of older machines.
  • The 8GB total capacity, while doubling typical stock configurations, remains a ceiling for users running virtual machines, professional creative applications, or modern browsers with heavy tab loads.
  • Installation requires physical access to the SO-DIMM slots, which on certain MacBook Pro models involves bottom panel removal — a process that voids AppleCare if still active and requires appropriate tools and static precautions.
  • The 1333MHz bus speed, appropriate for the target systems, offers no performance uplift over Apple's original factory RAM if the system was already configured at 1333MHz — only capacity increases, not bandwidth.

Frequently Asked Questions

The CT3309273 is engineered for select Apple iMac and MacBook Pro models that use DDR3 SO-DIMM slots operating at 1333MHz (PC3-10600). The exact compatible model list varies — Crucial's online compatibility tool cross-references by serial number or model identifier to confirm fit before purchase.
DDR3-1333 at 8GB shifts your system from relying on disk-based virtual memory (swap) for routine multitasking to keeping active processes in physical RAM. The practical result is faster application switching, reduced beach-ball spinning under moderate workloads, and noticeably quicker response when running several applications simultaneously. The 1333MHz bus speed matches what Apple specified for these systems, so you gain capacity without introducing a frequency mismatch.
PC3-10600 (1333MHz) is the correct rated speed for the Apple systems this kit targets. Installing faster DDR3 (e.g., PC3-12800 at 1600MHz) in a system specced for 1333MHz will typically result in the modules running at 1333MHz anyway — the memory controller defaults to the lower supported speed. The CT3309273 runs at the native specified frequency, which is the correct and stable configuration.
Crucial's lifetime warranty covers manufacturing defects in the memory modules themselves — dead-on-arrival failures, premature module failure, and similar hardware defects. It does not cover damage from improper installation, static discharge, or system-side incompatibility issues.
No — DDR3 SO-DIMM upgrades in compatible Apple systems are plug-and-play at the hardware level. macOS automatically recognizes the additional RAM after installation with no driver installation, firmware update, or system configuration required.

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