Crucial CT51264AC800 4GB DDR2 800MHz SODIMM Laptop Memory

Name: Crucial CT51264AC800 4GB DDR2 800MHz SODIMM Laptop Memory
Brand: Crucial
SKU: CT51264AC800

Overview

The Crucial CT51264AC800 is a 4GB DDR2-800 SODIMM — a 200-pin laptop memory module operating at 800MHz with CL6 latency. In DDR2 terms, this is top-tier: 800MHz is the highest standard DDR2 speed, delivering a theoretical peak bandwidth of 6.4 GB/s per channel. For laptops that shipped during the Core 2 Duo era with 1 or 2GB of RAM, jumping to 4GB (or 8GB with two modules) transforms the system from barely adequate under modern browsing workloads to genuinely usable for everyday tasks.

This module is built for users keeping older ThinkPads, MacBooks (pre-2009), and other DDR2-era notebooks in service — whether for a dedicated purpose like a network appliance, a lightweight Linux workstation, or simply extending the useful life of functional hardware. Crucial's compatibility database is one of the most reliable in the industry for legacy platforms, and the lifetime warranty provides long-term assurance. Installation is the standard SODIMM procedure: open the memory bay, seat the module at an angle, and press down until the clips engage. No BIOS configuration required on supported systems.

Key Features

Single Module

Specifications

Brand

Crucial

Model

CT51264AC800

Capacity

4GB

Memory Type

DDR2

Speed

800MHz (PC2-6400)

Form Factor

200-Pin SODIMM

CAS Latency

CL6

Module Count

Single Module

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Pros & Cons

👍 Pros

4GB capacity per module maximizes memory density for DDR2 platforms that often shipped with only 1–2GB from the factory.
800MHz (PC2-6400) speed runs at the top of the DDR2 specification, delivering 6.4 GB/s peak bandwidth per channel.
200-pin SODIMM form factor with broad backward compatibility down to DDR2-533 and DDR2-667 systems.
Crucial's lifetime warranty and extensive compatibility database reduce the risk of purchasing incompatible memory.

👎 Cons

DDR2 is three generations behind current DDR5 — this module only serves legacy systems with no forward migration path.
4GB is a hard ceiling per module on most DDR2 chipsets, limiting total system memory to 8GB in dual-slot laptops.
CL6 latency is standard but not exceptional — tighter timings are available from specialty vendors at a premium.
Single-module purchase means you'll need to source a second stick separately if you want dual-channel operation.

Frequently Asked Questions

What systems are compatible with the CT51264AC800?

This is a 200-pin DDR2 SODIMM running at 800MHz (PC2-6400). It fits any laptop with a DDR2 SODIMM slot that supports 800MHz or lower speeds. Most Intel Core 2 Duo-era notebooks from 2007–2010 qualify, but check your system's maximum supported RAM per slot — some older chipsets cap at 2GB per DIMM.

Will this module work if my laptop currently runs DDR2-667 memory?

Yes. DDR2-800 is backward compatible with DDR2-667 (PC2-5300) slots. The module will downclock to 667MHz to match the memory controller. You won't get 800MHz speeds, but it will function correctly.

Can I pair this 4GB module with a different-sized DIMM for 6GB total?

Technically yes — DDR2 does not require matched pairs to function. However, you'll lose dual-channel mode on systems that support it, which reduces memory bandwidth. For best performance, use two identical modules.

Is CL6 latency good for DDR2-800?

CL6 is the standard latency rating for DDR2-800. Lower latencies like CL5 exist but are rare and more expensive at this speed. CL6 at 800MHz delivers effective latency of 15 nanoseconds, which is typical and adequate for DDR2-era platforms.