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Western Digital WD7500AAKS 750GB SATA HDD
Date: Aug 03, 2007
Author: Shane Unrein
Introduction, Features & Specs

For several months, the battle for the biggest consumer hard drive was only fought by Hitachi and Seagate. First, only Seagate was in it with its 750GB hard drive using perpendicular recording technology. Then, Hitachi decided to skip 750GB and go straight to 1,000GB (1TB). Seagate has announced its 1TB hard drive, but we have yet to get one in our hands or see it in the retail channel. Recently, a new combatant finally stepped into the ring as well: Western Digital entered the fray with a 750GB offering.

We aren't sure why Western Digital waited so long to offer a drive bigger than 500GB, but we are happy to see the competition heating up. Plus, with storage prices so low right now, Western Digital's move seems rather smart. The company can offer its flagship drive (in terms of capacity) at a very attractive price. The MSRP for the new 750GB WD Caviar SE16 is only $249.99, which is roughly $0.33/GB.

The model number for the Western Digial Caviar SE16 drive that we have in the labs today is WD7500AAKS. This drive boasts 16MB of cache and a 3Gb/s transfer rate. Additionally, the drive features perpendicular recording, just like the 750GB Seagate Barracuda 7200.10 that we will be comparing it to in our benchmarks.

Western Digital Caviar SE16 WD7500AAKS
Specifications & Features
Capacity: 750 GB
Interface: SATA 3Gb/s
Spindle Speed: 7200 RPM
Cache Buffer: 16 MB
Height: 25.4 mm
Length: 147 mm
Width: 101.6 mm
Weight: 0.63 kg

Seek Times
Average Latency: 4.20 ms
Read Seek Time: 8.9 ms
Write Seek Time: 10.9 ms
Track-To-Track Seek Time: 2.0 ms
Full Stroke Seek: 21.0 ms

Transfer Rate

Buffer To Host (Serial ATA): 3 Gb/s (Max)
Buffer To Disk: 972 Mbits/s (Max)


Idle Mode: 28 dBA (average)
Seek Mode 0: 33 dBA (average)
Seek Mode 3: 29 dBA (average)

Power Requirements

Read/Write: 8.77 Watts
Idle: 8.40 Watts
Standby: 0.97 Watts
Sleep: 0.97 Watts

Top performance for Windows Vista
WD Caviar SE16 SATA and EIDE drives are certified for
     Windows Vista and are top performers on the Windows
     Vista Experience Index.

16 MB cache
Bigger cache means faster performance. A massive
     16 MB cache combined with advanced acoustic and
     power-reducing technologies make these ultra-fast
     drives the perfect solution for the fully loaded PC.

Perpendicular Magnetic Recording (PMR)
The latest generation of WD Caviar SE16 drives
     employs PMR technology to achieve even greater
     areal density. (750 GB only currently)

Calculates optimum seek speeds to lower power
     consumption, noise and vibration.

Parks the recording heads off the disk surface during
     spin up, spin down and when the drive is off. This
     ensures the recording head never touches the disk
     surface resulting in improved long term reliability due
     to less head wear, and improved non-operational
     shock tolerance.

The motor shaft is secured at both ends to reduce
     system-induced vibration and stabilize platters for
     accurate tracking, during read and write operations.
     (750 GB only currently)

3 Year Warranty (bare drive, 1 year for retail kit)

Although it didn't come in full retail trim, our sample came with all of the same goodies you would find in a retail package, including a Quick Install Guide, a CD with Data Lifeguard Tools, four screws and a Serial ATA cable with SecureConnect.

While the last WD Caviar SE16 drive we reviewed (the WD5000KS) included a 4-pin (Molex style) power connector, the WD7500AAKS does not. It only includes SATA power and SATA data connectors. There is also a set of 8 pins that can be jumpered for different settings. For instance, when pins 1 and 2 are jumpered, SSC (Spread Spectrum Clocking) is enabled.

Considering the benefits of perpendicular recording, it is nice to see more companies, like Western Digital, taking advantage of the technology (listed as PMR - perpendicular magnetic recording in the feature list above). Perpendicular recording allows for greater areal density by storing bits perpendicularly to the plane of the disc rather than parallel to it. In addition to introducing PMR to its Caviar SE16 line, the WD7500AAKS also features IntelliSeek, SecurePark, and StableTrac, which all combine for making a more attractive drive. Let's take it around the track for a couple laps and see how it performs.

Test System and SiSoft SANDRA

When testing the Western Digital WD7500AAKS SATA HDD, we used an Athlon 64 4600+ processor on a DFI LANParty NF4 SLI-DR motherboard. We also used 1GB of low latency Corsair DDR (TWINX1024-3200XL) and a 120GB Maxtor SATA hard drive for the operating system drive. The WD7500AAKS was compared to the following drives: a 500GB Western Digital WD5000KS Caviar SE16, a 750GB Seagate Barracuda 7200.10, a 500GB Seagate Barracuda 7200.9 and a 500GB Hitachi Deskstar 7K500.

HotHardware Test System
AMD Athlon 64 3800+ Powered

Processor -

Motherboard -

Video Card -

Memory -

Audio -

Hard Drives -


Hardware Used:
AMD Athlon 64 4600+

nForce4 SLI chipset

GeForce 8800 GTX

1024MB Corsair XMS PC3200 RAM

Integrated on board

Seagate Barracuda 7200.10

750GB - 7,200RPM - SATA 3Gb/s

Seagate Barracuda 7200.9
500GB - 7,200RPM - SATA 3Gb/s
Hitach Deskstar 7K500
500GB - 7,200RPM - SATA 3Gb/s
Western Digital WD5000KS
500GB - 7,200RPM - SATA 3Gb/s
Western Digital WD7500AAKS
750GB - 7,200RPM - SATA 3Gb/s

Operating System -
Chipset Drivers -
DirectX -

Video Drivers

Relevant Software:
Windows XP Professional SP2
nForce Drivers v6.86
DirectX 9.0c

NVIDIA ForceWare 162.18

Benchmarks Used:
SiSoftware Sandra
Futuremark PCMark05
HD Tach 3.0.1

We began our testing with SiSoftware's SANDRA File System benchmark module. This test's method of hard disk performance analysis it what we would consider a "light duty" consumer-level evaluation tool. The folks in IT would have your head for recommending a drive based solely on SANDRA File System test results. However, the benchmark is a popular utility within the performance PC enthusiast community, and it does provide a decent quick glance at high-level throughput characteristics of the total storage subsystem, which of course includes HDD controllers and other associated system components.

Preliminary Benchmarks With SiSoft SANDRA

The WD7500AAKS jumps right out of the gate to show the competitors who the new sheriff in town is. It ties for the highest Buffered Read score and soundly beats the other drives in the Sequential Read and Random Read tests. This is what we like to see because we tend to place more stock in the Sequential and Random Read tests since standard desktop and gaming application file access places moderate to high loads in these areas. In other words, these are the areas users would notice the performance gain.

And we thought the read scores above were impressive - The WD7500AAKS sets a new bar against other 7200 RPM drives in this test. Not only does the WD7500AAKS easily surpass its older, smaller brother (the WD5000KS), but it also shows the other perpendicular recording drive, the Seagate 7200.10 750GB, that Western Digital is not to be taken lightly.

Most of you are probably familiar with Sandra's Drive Index rating, and this graph basically does a nice job of summarizing what we saw above in the read and write tests. The WD7500AAKS is the leader among all of the drives tested. So far, we are very impressed. Let's see if the trend continues in the other benchmarks.

Futuremark PCMark05

Next up is PCMark05 from FutureMark Corp. We specifically used only the HDD Test module of this benchmark suite to evaluate all of the drives we tested versus the WD7500AAKS. We consulted Futuremark's white paper on PCMark05 for an understanding of what this test component entails and how it calculates its measurements.

Futuremark's PCMark05

Courtesy, Futuremark Corp. -
For these tests, we use RankDisk, an application developed and copyrighted by Intel. In our testing, we found RankDisk to be suitable for a neutral benchmark. RankDisk is used to record a trace of disk activity during usage of typical applications. These traces can then be replayed to measure the performance of disk operations for that usage. RankDisk records disk access events using the device drivers and bypasses the file system and the operating system's cache. This makes the measurement independent of the file system overhead or the current state of the operating system. In replaying traces, RankDisk always creates and operates on a new "dummy" file. This file is created in the same (or closest possible) physical location of the target hard disk. This allows the replaying of traces to be safe (does not destroy any existing files) and comparable across different systems. The traces contain different amount of writing and reading on the disk; total ratio in the HDD test suite disk operations is 53% reads and 47% of writes.  The following input traces are used:

Windows XP Startup:  This is the Windows XP start trace, which contains disk activities occurring at operating system start-up. The test is 90% reading and 10% writes. This trace contains no user activity.

General Hard Disk Drive Usage:  This trace contains disk activities from using several common applications.
These are:
- Opening a Microsoft Word document, performing grammar check, saving and closing
- Compression and decompression using Winzip
- Encrypting and decrypting a file using PowerCrypt
- Scanning files for viruses using F-Secure Antivirus.
- Playing an MP3 file with Winamp
- Playing a WAV file with Winamp
- Playing a DivX video using DivX codec and Windows Media Player
- Playing a WMV video file using Windows Media Player
- Viewing pictures using Windows Picture Viewer
- Browsing the internet using Microsoft Internet Explorer
- Loading, playing and exiting a game using Ubisoft™ Tom Clancy's Ghost Recon
The General Usage trace is 60% reads and 40% writes.

Virus Scanning:  Virus scanning is a critical task in today's PC usage. As the major bottleneck of scanning viruses is in hard disk activity, it is reasonable to include virus scanning as a HDD test. The test consists of HDD activity of scanning 600MB of files for viruses. The Virus Scanning test is mostly disk reading (99.5%).

The PCMark05 tests reveal results similar to those in Sandra. When it comes to the General Usage and XP Startup tests, the WD7500AAKS performs quite well, besting all of the competition. Additionally, the it outperforms all of the other drives in the Virus Scan test by about 2MB/s or more.

PCMark05's overall Hard Disk Drive test score is representative of a weighting of two other tests in addition to the tests we've given detail for above, specifically File Write and Application Loading. In our previous Western Digital review, the WD5000KS whooped on the competition, but it can't hang with the WD7500AAKS. The WD7500AAKS grabs an almost 7% lead over the WD5000KS.

HD Tach 3.0.1

The four HD Tach metrics that we sampled for each drive are Random Access, which is largely dependent on spindle speed of the drive, Read Average, Write Average and Burst Read throughput. Again, Read and Write Average scores are what we would consider the most meaningful to the end user. On the other hand, Burst Read is typically tied to a drive's on-board caching and SATA interface speed.

Performance With HD Tach

After the WD7500AAKS's apparent dominance in the eariler tests, we finally find a kink in its armor -- the HD Tach Burst Read test. While it does outperform the other Western Digital drive and the Hitach drive in Burst Read, it can't quite touch the scores put up by the two Seagate drives. Once again, we have to stress that we put more weight in the Average Read and Average Write speeds, and these are two areas where the WD7500AAKS dominates again.

Performance Summary and Conclusion

Performance Summary: The benchmarks speak for themselves: Western Digital took the winning Caviar SE16 formula, added perpendicular recording, and created a huge, yet speedy 7200RPM hard drive in the form of the WD7500AAKS. We took special note of how much better Western Digital's first generation perpendicular recording drive performed than Seagate's (the 750GB Barracuda 7200.10) in our testing. Overall, none of the other drives could touch the WD7500AAKS in our benchmarks.

With the excellent performance offered by the WD7500AAKS, we were a little disappointed that we didn't have two drives to show you some RAID 0 action. Regardless, we were happy to see Western Digital enter the huge hard drive battle with a solid contender, which also happens to be the fastest 7200RPM drive we've had the pleasure to test so far. We'd love to pit it against a 1TB Hitachi and one of Seagate's new 7200.11 drives to see which one is truly the current king.

In many ways, we feel almost the same about the WD7500AAKS as we did about the WD5000KS. We can't find anything to dislike about the WD7500AAKS, but it would be nice to see Western Digital (and other storage companies) match Seagate's 5-year warranty. When it comes to storage, we think everyone can agree that the longer the warranty is, the better off consumers are.

The WD7500AAKS is now the largest Caviar SE16 drive offered by Western Digital, and it is the first drive offered by the company to feature perpendicular magnetic recording. With great features and an affordable price, the WD7500AAKS demonstrates that you can have huge storage capacity and awesome performance in one drive. If you have masssive storage needs, we wholeheartedly recommend Western Digital's 750GB WD7500AAKS Caviar SE16 SATA HDD.

•  Top notch performance
•  Great street price
•  Big, big, big
•  3-year warranty

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