Western Digital WD6400AAKS Internal Hard Disk
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Western Digital WD6400AAKS 640GB Hard Drive Caviar Blue 7.2K Refurbished

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Part Number#: WD6400AAKS
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Short Description:
WD6400AAKS Caviar Blue 640 Gigabytes (GB) 7200 Revolutions Per Minute(RPM) Serial Advanced Technology Attachment (SATA) 16 Megabytes (MB) Buffer Cache 3.5inch Large Form Factor (LFF) Internal Hard Disk Drive | Made by Western Digital | Refurbished
Western Digital
Product Condition:
Warranty provided by ALLHDD.COM:
30 Days

Overview of the Western Digital WD6400AAKS 640GB Hard Disk Drive

The Western Digital WD6400AAKS Caviar Blue is a 3.5-inch internal hard disk drive, designed and manufactured by Western Digital Corporation, one of the leading companies in the data storage industry. This particular HDD model offers a storage capacity of 640 gigabytes (GB), operates at a speed of 7200 revolutions per minute (RPM), and utilizes a Serial Advanced Technology Attachment-SATA interface. Additionally, it features a 16-megabyte (MB) buffer cache, making it suitable for various computing tasks, from everyday use to more demanding applications.

Understanding the Basics of 7.2K RPM SATA Internal HDD

Before we dive into the details of the Western Digital WD6400AAKS Caviar Blue, let's break down some of the fundamental terms and concepts that are essential for a better understanding.

640 Gigabytes

A gigabyte (GB) is a unit of digital information storage capacity. In this context, the Western Digital WD6400AAKS Caviar Blue provides 640 GB of storage, which is equivalent to approximately 640 billion bytes of data. This ample storage capacity allows users to store a wide range of data, including documents, photos, videos, and software applications.

Revolutions Per Minute

The revolutions per minute (RPM) is a measure of the rotational speed of the HDD's platters. In the case of the Western Digital WD6400AAKS Caviar Blue, it operates at 7200 RPM. Higher RPM values typically indicate faster data access and transfer speeds, making this HDD suitable for tasks that require quick access to data, such as gaming or video editing.

Serial Advanced Technology Attachment-SATA

SATA is a widely used interface for connecting storage devices to a computer's motherboard. The Western Digital WD6400AAKS Caviar Blue uses a SATA interface, which is known for its ease of use, compatibility with most modern computers, and efficient data transfer capabilities.

3.5-inch Large Form Factor-LFF

The 3.5-inch form factor refers to the physical size of the hard drive. A 3.5-inch drive is larger than the more compact 2.5-inch drives commonly found in laptops. This larger form factor is commonly used in desktop computers and provides additional space for higher storage capacities.

Performance of 7200 RPM

RPM, or Revolutions Per Minute, is a critical parameter when assessing the performance of an HDD. The Western Digital WD6400AAKS Caviar Blue operates at 7200 RPM, which means the hard drive's platters spin at a speed of 7200 revolutions per minute. This high RPM value indicates that the data can be read and written more quickly compared to slower drives with lower RPM ratings.

Faster RPM values translate to faster data access times. This is particularly important when it comes to tasks like loading large files, running applications, or even gaming. If you need a hard drive that can keep up with your data demands, the WD6400AAKS with its 7200 RPM is a solid choice.

Cache Size 16MB

The cache size of a hard drive, often referred to as the buffer cache, plays a significant role in its performance. The Western Digital WD6400AAKS Caviar Blue comes with a 16 Megabyte (MB) buffer cache. The buffer cache serves as a temporary storage area for frequently accessed data, reducing the time it takes to retrieve this data from the platters.

In practical terms, a larger cache can lead to improved performance, especially when dealing with small, random reads and writes. This can benefit tasks like loading software or accessing frequently used files more quickly. The 16MB cache size of the WD6400AAKS is a good balance for general-purpose computing tasks.

Features of the Western Digital WD6400AAKS Caviar Blue

Now that we have a solid understanding of the fundamental terms, let's explore the features of the Western Digital WD6400AAKS Caviar Blue that make it a standout choice for data storage.

High Storage Capacity

With 640 GB of storage, this HDD offers ample space for storing a wide range of digital content, from your important documents and files to multimedia collections, games, and more. This makes it an ideal choice for individuals and businesses with significant data storage requirements.

Speedy Performance

The 7200 RPM rotational speed of the Western Digital WD6400AAKS Caviar Blue ensures that data access and transfer operations are quick and efficient. This performance feature is especially beneficial for tasks that demand fast data retrieval, such as loading large applications, playing high-resolution videos, and multitasking.

Efficient Data Management with Buffer Cache

The 16 MB buffer cache in this HDD enhances its overall performance by temporarily storing frequently accessed data. This feature reduces the time it takes to read and write data, resulting in smoother and more responsive computing experiences.

Performance and Reliability

When it comes to choosing a hard drive, performance and reliability are two key factors to consider. Let's take a closer look at how the Western Digital WD6400AAKS Caviar Blue performs and why it's considered a reliable option.

Speed and Responsiveness

The 7200 RPM speed of this HDD ensures rapid data access and transfer. This is particularly advantageous for tasks that require quick data retrieval, such as gaming or editing large multimedia files. Additionally, the 16 MB buffer cache plays a significant role in optimizing the drive's performance by temporarily storing frequently used data and reducing read and write times.


Western Digital is a reputable manufacturer with a history of producing reliable hard drives. The Caviar Blue series, to which the WD6400AAKS belongs, is known for its durability and long-term performance. The drive is built to withstand the rigors of daily use and is designed to provide years of trouble-free storage.

Ideal for Various Applications

The combination of high storage capacity, speed, and reliability makes the Western Digital WD6400AAKS Caviar Blue suitable for a wide range of applications. It can be used for:

  • General Data Storage: Whether you need to store documents, photos, or videos, the large capacity of this HDD allows you to keep all your data in one place.
  • Gaming: Gamers can benefit from the fast data access speeds, reducing loading times and improving the overall gaming experience.
  • Multimedia Editing: Video and photo editors can take advantage of the storage capacity and speed when working on large media files.
  • Business Use: The drive can be employed for backing up important business data or serving as a network-attached storage (NAS) solution for small businesses.

Significance of SATA Connectivity

The Western Digital WD6400AAKS uses a SATA interface, specifically SATA 3.0 Gb/s, which is a common standard for connecting storage devices to a computer. Understanding the importance of SATA connectivity is crucial:

  • Compatibility: SATA is widely supported by most modern motherboards, ensuring that the WD6400AAKS is compatible with a broad range of systems. It's a plug-and-play solution for many users.
  • Hot Swapping: SATA interfaces often support hot-swapping, allowing users to add or remove drives without powering down the system. This feature can be advantageous for those who frequently upgrade or swap out drives.
  • Data Transfer Speed: While the WD6400AAKS uses SATA 3.0 Gb/s, it's essential to recognize that the maximum data transfer rate of the drive may be lower. The actual transfer speed depends on the drive's internal mechanisms and capabilities.
  • Cable Management: SATA cables are relatively small and easy to manage, making them suitable for tidy cable routing inside a computer chassis.
  • Power Efficiency: SATA interfaces are designed with power efficiency in mind, which can lead to lower energy consumption compared to older connection types.

Buffer Cache in Data Handling

Buffer cache, often referred to as cache memory, plays a crucial role in enhancing the performance of the Western Digital WD6400AAKS HDD. The WD6400AAKS is equipped with a 16MB buffer cache, which is a temporary storage area for frequently accessed data. Here's why buffer cache is significant:

  • Faster Data Retrieval: Frequently accessed data is stored in the buffer cache, which allows for faster retrieval. This can lead to quicker application loading times and smoother overall system performance.
  • Improving Multi-Tasking: When multiple applications or tasks are running simultaneously, the buffer cache helps manage and prioritize data requests, reducing latency and improving responsiveness.
  • Reducing Wear and Tear: By storing frequently accessed data in the cache, the HDD can minimize the number of times it needs to access the physical platters. This can extend the lifespan of the drive.
  • Smoother Media Playback: Buffer cache can significantly enhance the playback of multimedia content, ensuring that video and audio files play without interruptions or delays.
  • Write Performance: Buffer cache also benefits write operations by temporarily storing data before it's written to the disk. This can improve write performance, especially for small files.

Main Information about this Western Digital WD6400AAKS

  • Manufacturer: Western Digital
  • Part Number or SKU# WD6400AAKS
  • Device Type: Hard Disk Drive
  • Interface: SATA-II

Technical Information of Internal Hard Drive

  • Product Line: WD Caviar
  • Form Factor: 3.5 Inch x 1/3H
  • Storage Capacity: 640GB
  • Serial ATA-300
  • Buffer Size: 16MB
  • SecurePark
  • StableTrac
  • IntelliSeek
  • Perpendicular Magnetic Recording (PMR)
  • Compliant Standards: S.M.A.R.T.


  • Drive Transfer Rate: 300 MBps
  • Seek Time: 8.9 ms (average)
  • Track-to-Track Seek Time: 2 ms
  • Average Latency: 4.2 ms
  • Spindle Speed: 7200 rpm


  • Storage Hard Drive / Non-Recoverable Errors 1 per 10^15
  • Start / Stop Cycles 50,000

Expansion / Connectivity

  • 1 x Serial ATA-300 - 7 pin Serial ATA
  • Compatible Bays: 1 x Internal - 3.5 Inch x 1/3H


  • Microsoft Certifications Works with Windows Vista
  • Compliant Standards RoHS

In summary, the Western Digital WD6400AAKS Caviar Blue is a reliable, well-rounded internal hard disk drive that strikes a balance between storage capacity and performance. With 640GB of space, a 7200 RPM speed, a 16MB cache, and a SATA interface, it can meet the storage needs of a wide range of users. Its 3.5-inch form factor is well-suited for desktop systems.

When considering this hard drive, keep in mind its compatibility with your computer and your specific use case. Regular maintenance, such as keeping your system cool and performing backups, can help ensure the longevity of your drive.

The Western Digital WD6400AAKS Caviar Blue remains a viable choice for those seeking reliable and cost-effective storage solutions for their desktop computers. Whether you're storing documents, multimedia files, or running applications, this hard drive can deliver the performance and capacity you need.

Western Digital
Product Condition:
Warranty provided by ALLHDD.COM:
30 Days

About Refurbished Products

Refurbished products are typically refurbished by an Original Manufacturer or an affiliate of the manufacturer or 3rd party facility. This product may have minor blemishes due to normal product usage and doesn't necessarily come with documentation and software unless indicated, but has been well tested and generally has never had any defects.

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