Western Digital WD4000AAJS 400GB SATA Hard Drive

Western Digital Part #/MPN: WD4000AAJS

DiscTech Item #: WDC-WD4000AAJS-RF-OE

  • Special Order - Ships in 5-10 business days
    Special Order - Ships in 5-10 business days

    This item has a lead time for fulfilment (as listed), this is approximate. Your credit card will be authorized in full on the day of ordering; it will not be charged until the day of shipment.


Capacity: 400GB

Speed: 7,200RPM

Interface Types: SATA

Form Factor: 3.5inx1.0in LFF Hard Drive

Sector Size: 512 / 512e

Sustained Throughput: 300

Average Seek Time: 8.9

Electrical Interface: SATA 300 - 3.0Gbps

On-Board Cache: 8MB

Western Digital WD4000AAJS 400GB 3.5in 3Gbps 7.2K RPM Caviar SE SATA HDD - Refurbished

Western Digital WD4000AAJS 400GB 3.5" 3.0 Gbps 7200 RPM Caviar SE Serial ATA Hard Disk Drive - Refurbished

WD Caviar® SE
Desktop Hard Drives

Cool-running, superior performance, and industry-leading reliability make these drives the perfect hard drives for desktop, business, and consumer electronics storage — ideal for high-performance family computing such as photo editing, multimedia functions, and business applications such as spreadsheets and databases.

Product Benefits

Fast — WD, the first to introduce an 8 MB buffer, has advanced the caching algorithms of this new and improved family of hard drives, resulting in next-generation high performance.

Cool — Heat is a major contributor to hard drive wear, and cool drive operating temperatures help increase long-term drive reliability. WD achieves the lowest operating temperature of any hard drive in its class by lowering the drive’s power consumption through advanced design of electronics and firmware.

Data Lifeguard Tools™ — This software utility works with embedded Data Lifeguard™ features (including shock protection, an environmental protection system, and error detection and repair) to make hard drive installation, management, and diagnostics simple and worry-free.


This drive is compatible with any server that accepts 3.5"x1.0" (LFF) SATA drives.

Model NumberWD4000AAJS
Formatted Capacity400,088 MB
Used Sectors Per Drive781,422,768
Interface300 MB/s Serial ATA 2.0 (backwards compatible with Serial ATA 1.0)
Bytes Per Sector512
Dedicated Landing ZoneYes
Actuator Latch/Auto ParkYes
Data Transfer Rate (maximum)
- Buffer to Host

300 MB/s max
Average Read Seek8.9 ms (average)
Track-to-track Seek2.0 ms (average)
Full Stroke Read Seek21 ms (average)
Average Latency4.2 ms
Rotational Speed7200 RPM
Read CacheAdaptive
Write CacheYes
Buffer8 MB
Drive Ready Time9.0 sec average
Start/Stop Cycles50,000 min
Error Rate (non-recoverable)<1 in 10e14 bits read
LBA supportYes
Height1.028 in (25.4 mm) max)
Length5.787 in (147.0 mm) max
Width4.0 in (101.6 mm) ± .01 in.
Weight1.32 lb (0.60 kg) ± 10%
- 12 V (± 10%)
- 5V(± 5%)
- Power

450 mA
800 mA
9.50 W
- 12 V (± 10%)
- 5V(± 5%)
- Power

430 mA
730 mA
8.75 W
- 12 V (± 10%)
- 5V(± 5%)
- Power

20 mA
270 mA
1.60 W
- 12 V (± 10%)
- 5V(± 5%)
- Power

20 mA
250 mA
1.50 W
- Operating (2ms)
- Non-operating (2ms)
- Half sine wave measured in 2 ms

duration, measured withough isolation
- Random
- Linear
- Linear

0.004 g2 / Hz (10 to 300 Hz)
20-300 Hz, 0.75G (0 to peak)

5-20 Hz, 0.195 inches (dbl amp)
20-500 Hz, 4G (0 to peak)
Operating Temperature and Humidity
- Temperature
- Humidity
- Thermal Gradient

5°C to 55°C (41°F to 131°F)
5-95% RH non-condensing
20°C/hour (maximum)
Non-Operating Temperature and Humidity
- Temperature
- Humidity
- Thermal Gradient

-40°C to 65°C (-40°F to 149°F)
5-95% RH non-condensing
30°C/hour (maximum)
Acoustics (average)
- Idle Mode
- Seek Mode 0
- Seek Mode 3

26 dBA
31 dBA
27 dBA

Click here to view the manufacturer's item description/brochure

ROHS Compliant

Weight: 1.8 lb

Warranty: 1 Year DiscTech


Condition Levels Explained

These products have had NO problems or failures, they merely have some usage. The product has been professionally returned to excellent condition. These items have been fully tested, formatted (if appropriate) &repackaged. Hard drives are fully vetted for surface defects and wear, only healthy disks are approved for resale to our customers. Please see our refurbishing process for more details. Watch a video about our refurbishing process

1 Year DiscTech Warranty

Product Warranties Explained

The product has a DiscTech warranty for the time period specified. View our limited warranty