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Western Digital drives: Raptor 74 & Caviar SE 250

May 18, 2005 by Devon
Cooke
and Mike
Chin

Products

Western Digital Raptor WD740GD

74GB, 10,000 RPM Hard drive

Western Digital Caviar SE
WD2500JD

250GB, 7,200 RPM Hard drive

Manufacturer
Western
Digital
Market Price
Raptor WD740GD: ~US$180

Caviar SE 2500JD:
~US$130

Sometime around the beginning of the year, Western Digital completed a year-long
transition to Fluid Dynamic Bearing (FDB) motors across their entire product
line. While this transition meant little in terms of performance, FDB motors are known to be significantly quieter than the ball-bearing
motors that they replaced. Since Western Digital drives have never had a good
reputation for noise, does the change in motor bearings warrant
revising our opinion of them? That's the question this review intends to answer.

But some of you may be wondering, What are Fluid Dynamic Bearing (FDB) motors and what are their advantages over conventional Ball Bearing Motors?

To answer this question, we turn to a white paper entitled Fluid Dynamic Bearing Spindle Motors: Their future in hard disk drives by Walker C. Blount, Senior Engineer at Hitachi Global Storage Technologies:



©
Hitachi Global Storage Technologies

  • Non Repeatable Run-Out (NRRO) the highest contributor to Track Mis-Registration (TMR)... There is an upper limit at which the Ball Bearing design can no longer overcome the NRRO problem at the higher areal densities. Currently with Ball Bearings, NRRO has settled in the 0.1 micro-inch range. By contrast, FDB generates less NRRO due to the higher viscosity of lubrication oil between the sleeve and stator. FDB designs are expected to limit NRRO in the range of 0.01 micro-inch.
  • Desktop and mobile HDD track densities today are exceeding 100,000 tracks per inch (100 kTPI), which can compound the issues of NRRO. Incorporating FBD motors in the design of desktop and mobile hard drives solves many of the issues of NRRO.
  • FDB motors provide additional shock resistance beyond that of Ball Bearing spindle motors. A contributing factor is the additional surface area inherent in the FDB design. There is more conforming surface contact through the lubricant as compared to the Ball Bearings and raceway surface contact of the Ball Bearing design. Additionally, the lubricant film provides additional damping to shock.
  • The source of acoustic noise in the HDD is the dynamic motion of the disk and spindle motor components. The sound components are generated from the motor magnet, stator, bearings, and disks. These sound components are all transmitted through the spindle motor to the HDD base casting and top cover. Eliminating the bearing noise by use of FDB spindle motors reduces one area of the noise component that contributes to acoustic noise. In addition, the damping effect of the lubricant film further attenuates noise contributed from the spindle motor components. This results in lower acoustic noise from HDDs employing FDB spindle motors. Industry data has shown a 4dBA or more decrease in idle acoustic noise or some HDD designs.

There are other good reasons to take a second look at Western Digital. The Raptor WD740GD
is the first (and so far only) 10,000 RPM ATA drive on the market, and, despite
its billing as an "Enterprise class" drive, it is popular with the
high-end gaming crowd for its fast seeks and load times. If this drive turns out to be quiet, it would be an exciting counterpoint to the truism that you must sacrifice performance to gain silence. As with most 10,000 RPM drives, the downside of the Raptor is its small capacity.

WESTERN DIGITAL RAPTOR (from WD's
data
sheet
)
FEATURE & BRIEF COMMENT

Built for speed – with 10,000 RPM rotational disk speed
and average data seek as fast as 4.5 ms. Exceeds SCSI 10,000 RPM
products in workstation benchmarks.

Truly, unique in its class. There are no other 10,000 RPM ATA
drives.

Enterprise-class throughput – includes Western Digital's
Ultra/150 Command Queuing technology that optimizes the sequence
of data transfers to the hard drive from the host, providing increased
data transfer efficiency resulting in higher performance for enterprise
applications
. (74 GB drive only)

Useful for server performance,
less so for desktop use.

Built for reliability – features a rugged, enterprise-class,
mechanical platform with fluid dynamic bearings and high-end actuator.

As mentioned, FDB drives
tend to be quieter than ball-bearing models.

Built to last – made for years of high-performance operation
around the clock. Mean Time Between Failure (MTBF) has been calculated
at 1.2 million hours.

An odd specification
that is hard to interpret without a degree in statistics. Few other manufacturers
list MTBF.
Built for enterprise
environments
– includes Enterprise Extensions S.M.A.R.T. Accessed
(EESA), an expanded command set that provides SCSI-like control for server
environments, as well as Rotary Acceleration Feed Forward™ (RAFF™)
that optimizes operation and performance when the drives are used in vibration-prone
multi-drive systems, such as rackmounted servers.
More enterprise-class
features.
Built with a backing
– carries Western Digital’s five-year warranty.
Good long after it becomes
obsolete.

Built for value – offers the performance and reliability
of Parallel SCSI drives at significantly less cost.

But significantly more
expensive per GB than other ATA drives.

The Caviar SE WD2500JD , the second WD under review, is a more conventional 7,200 RPM drive in a series that makes up the bulk
of Western Digital drives available through normal retail channels.
It is available in capacities ranging from 40 GB to 320 GB. The "SE"
in its name denotes an 8 MB cache — hardly an uncommon feature any more, but enough
to differentiate it from the 2 MB version.

WESTERN DIGITAL CAVIAR SE (quoted from Western Digital's
data
sheet
)
FEATURE & BRIEF COMMENT

Fast – WD, the first to introduce an 8 MB buffer, has advanced
the caching algorithms
of this new and improved WD Caviar family of
hard drives, resulting in next-generation high performance – performance
that matches the speed of most 16 MB cache drives.

Sound like a techno-marketingspeak explanation of the drive's performance.

Cool-running – 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, including slower drives spinning at 5400
RPM, by lowering the drives’ power consumption through advanced
design of electronics and firmware.

We'll
see if their "advanced design" is any more advanced than their
competitors' when we examine power draw.

Quiet – Today’s PCs, digital video recorders, and gaming
machines are increasingly operated in environments where noise is less
tolerated. WD minimizes WD Caviar noise

to levels virtually below the threshold of human hearing with its WhisperDrive™
technology which features a highly efficient power driver design
.
And to cut seek noise,

Soft Seek™ technology streamlines read/write seeking algorithms,
resulting in the drive operating more efficiently when accessing and writing
data.

Is it possible
that WhisperDriveis just FDB and Soft Seek is AAM? We don't
care what it's called so long as it really is quiet.

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

Freely available
for download, and seemingly compatible with non-WD drives.
SecureConnect™
– provides a 500 percent stronger cable-to-drive connection
than first-generation SATA hard drives and cables. Also ensures backward
compatibility with legacy SATA cables and backplanes.
A welcome
improvement, but a proprietary cable must be purchased.
FlexPower™
– connector technology that accepts power from both industry-standard
and new SATA power supplies.
This last
feature is a byproduct of using a PATA to SATA logic bridge.

A CAUTION: FDB MOTOR MODELS ONLY!

This review applies specifically to samples with Fluid Dynamic Bearing (FDB)
motors. As mentioned, only newer Western Digital drives use this technology,
so this review does not apply to older versions of the drives in question, even
though they may have the same model number. In the past, there has been considerable
confusion about which of Western Digital's drives use FDB motors; so much so
that for a little while two separate model numbers were used to distinguish
FDB and non-FDB models. Now that Western Digital has completely stopped producing
ball-bearing drives, they have reverted to the previous model nomenclature.

This is not a big problem for the large capacity drives that we are reviewing
— ball-bearing versions were likely produced in small numbers or never
at all — but lower capacity
ball-bearing models may still be available in retail channels. For example,
the model number for a brand new WD1200JB (120 GB PATA Caviar SE) is the same
as the original version that was manufactured with a ball-bearing motor when
it was released three years ago.

The most reliable way of acquiring an FDB drive is to look for the date of
manufacture printed on the exterior of the drive. Any date past January 2005
should guarantee that the drive contains an FDB motor. There is some unconfirmed anecdotal
evidence that Caviar drives with black faceplates all have FDB motors.

SPECIFICATIONS

The specifications below are specific to the models that we examined. Capacity, cache size, platter number, interface, and even performance vary from
model to model even within a single product line. Acoustics and power dissipation also vary depending on the number of platters
in the drive; smaller capacity drives tend to have fewer platters, and
tend to produce less noise and use less power.


Manufacturers' Specifications
HDD Model
Western Digital Raptor WD740GD
Western Digital Caviar SE WD2500JD
Capacity
74 GB
250 GB
Cache
8 MB
8 MB
Platters
2
3
Rotation Speed
10,000 RPM
7,200 RPM
Interface
SATA
SATA
Latency
2.99 ms
4.2 ms
Average Seek
4.5 ms
8.9 ms
Start/Stop cycles
20,000
50,000
Operating Temperature
5 - 55°C
5 - 55°C
Power Dissipation: Idle / Seek
7.90 / 8.40 W
8.75 / 9.00 W
Acoustics: Idle / AAM seek / normal
seek
32 / – / 36 dBA (no distance/angle given)
28 / 33 / 35 dBA (no distance/angle given)

If the SPL specs are for one meter distance, they are not promising at all. One has to wonder if the acoustics data is outdated (perhaps based on their ball bearing versions?), as our results were much better.

WESTERN DIGITAL RAPTOR

Although the Raptor is Western Digital's enterprise class ATA drive, it has found
a niche as a top-performing single-user drive. Its ATA interface makes it attractive
for use in desktop machines but also reduces its usefulness in the server market,
which is dominated by SCSI drives. Additionally, even though a version of command
queuing is implemented in the drive, there are few drive controllers that can
take advantage of it. Command queuing is quite beneficial for to server performance but offers
little benefit to single users.

Western Digital is selling the Raptor on price, performance and reliability. Although expensive
for a SATA-based drive, it is still cheaper than most of the SCSI drives that
it is competing against.

The reliability of the Raptor is a bit of a puzzle. Western Digital offers
a long, five-year warranty for the drive, so they must have some confidence
in the drive, but its start/stop cycle rating is only 20,000 — less than
half of the 50,000 that is standard for 7,200 drives. Of course, because it
is sold an an enterprise drive, it is probably intended to operate continuously
without spinning up or down. The number that Western Digital wants you to look
at is MTBF — Mean Time Between Failure — estimated at 1.2 Million
hours. Unfortunately, it is quite difficult to interpret what this means in
real terms, and it is very difficult to judge just how reliable the drive is
because few other manufacturers specify MTBF for their drives.

One thing to consider is that reliability is correlated to the amount of heat
a drive produces. The casing for the Raptor is heavily ridged, which should
allow it to dissipate more heat than usual. These may be necessary to dissipate
the additional heat generated by its 10,000 RPM spindle speed.



The sides of the raptor are ridged to increase heat dissipation.

WESTERN DIGITAL CAVIAR SE

It's difficult to tell how the Caviar SE compares to other drives by examining
it's "feature" sheet. Not surprisingly, most of the listed features
relate to performance, but it is difficult to read through the trademarked names
and vague descriptions to find out which of them are genuine features and which
are standard on all drives. The ones we are most interested in are related to
noise: WhisperDrive™ and Soft Seek™.

Soft Seek is almost certainly an implementation of AAM that trades a small
amount of seek performance for quieter seeks. Depending on the drive, AAM can
reduce seek noise to near inaudible levels or have next to no effect. We will
be sure to test how this drive behaves later on.

The description of WhisperDrive is a little more obscure. It reminds
me of Intel's Centrino "technology" which names a system
of features, not a single technology. Part of WhisperDrive is probably
the FDB motor that prompted this review, but we have no idea what is meant by
a "highly efficient power driver design" (sure sounds good though).

One feature that does seem to be unique to Western Digital drives is the SecureConnect SATA connector that is supposed to be five times stronger than the standard
SATA connector. We have no idea how Western Digital measured the strength of
the connection, but, given the flimsy quality of most SATA connectors, we welcome
this attempt at improvement. Unfortunately, we were unable to actually test
the connector because it requires a proprietary cable that was not shipped with
our test sample. A close examination of the SATA socket reveals a small hole
to one side of it. Our guess is that the special cable is designed to latch
into this hole to provide a secure connection.

TEST RESULTS

Our samples were tested according to our standard
hard drive testing methodology
. Our methodology focuses specifically on
noise, and great effort is taken to ensure it is comprehensively measured
and described. Performance is not tested, for reasons discussed in detail in the methodology article. For comprehensive HDD performance testing results, we recommend Storage Review, who have established a long reputation as the specialist in this field. We refer to Storage Review as a reference for many aspects of HDD performance.

Our test drives were compared against our reference drives, the
Seagate Barracuda IV and Samsung Spinpoint P80, that are profiled in our methodology
article. To get a good idea of where the drives in this review stand, it is
important to read the methodology article thoroughly.

Two forms of hard drive noise are measured:

  1. Airborne acoustics
  2. Vibration-induced noise.

These types of noise impact the subjective
perception of hard drive noise differently depending on how and where the drive
is mounted.

Both forms of noise are evaluated objectively and
subjectively. Both the subjective and objective analyses are essential to understanding
the acoustics of the drives. Airborne acoustics are measured using a professional
caliber SLM with absolute sensitivity below 0 dB. Measurements are taken at
a distance of one meter above the top of the drive using an A-weighted filter.
Vibration noise is rated on a scale of 1-10 by comparing against our standard
reference drives.

Ambient noise at the time of testing was 18 dBA.

RAPTOR & CAVIAR SE NOISE EVALUATION
Drive

Mfg date

firmware version

Vibration

1-10

(10 = no vibration)

Activity State

Airborne Acoustics


Measured Power

Western Digital Raptor WD740GD

February 2005

firmware 31.08F31
6
Idle

21 dBA/1m

7.4 W
Seek (AAM)

24-26 dBA/1m

11.5 W
Seek (Normal)

25-26 dBA/1m

11.9 W
Western Digital Caviar SE WD2500JD

March 2005

firmware 31.08F31
6
Idle

22 dBA/1m

7.1 W
Seek (AAM)

23-24 dBA/1m

8.2 W
Seek (Normal)

28-30 dBA/1m

10.7 W

For comparison, here is the data for SPCR's quiet 3.5" reference drives.

SPCR REFERENCE 3.5" DRIVES NOISE EVALUATION
Drive Model

Mfg date - firmware

Vibration

1-10

(10 = no vibration)

Activity


Airborne Acoustics


Power

Seagate Barracuda IV

ST340016A - firmware 3.10
6
Idle


20 dBA/1m


6.7 W

Seek (AAM)


23 dBA/1m



11.3 W

Seek (Normal)


25-26 dBA/1m



11.6 W

Samsung Spinpoint P80 (Nidec motor)

June 04 - firmware TK100-24
4
Idle


21 dBA/1m


6.3 W

Seek (AAM)


23-24 dBA/1m


8.3 W

Seek (Normal)


25-26 dBA/1m


9.1 W

Samsung Spinpoint P80 (JVC motor)

Feb 05 - firmware TK200-04
6
Idle


21 dBA/1m


6.2 W

Seek (AAM)


25 dBA/1m


n / a
Seek (Normal)


27 dBA/1m


9.3 W

NOTE: The acoustics detailed below were assessed after prolonged, very close listening, with the drives as close as a few inches from our ears at times. The subjective descriptions may not match the MP3s of the drives, due to unavoidable losses in audio recording and in your playback system. Whether the described acoustic characteristics are audible inside a case in a working system will depend greatly on the specifics of your system build, the ambient noise level and your own aural sensitivity. Whether you choose to give more weight to our subjective descriptions or to the audio recordings or the SPL measurements will depend largely on your own biases — consider them all for the most balanced perspective.

Raptor

The dual platter Raptor impressed us with its idle noise. There is no motor noise
to speak of; the only noise is the whoosh of airflow across
the spinning platters. The overall volume is slightly louder than our favorite reference
drive — the Barracuda IV — gauged by listening and by SPL measurements. It actually matches our reference quiet Samsung (Nidec motor) drives for idle SPL.

We can vouch for the Raptor's reknown speediness, even though we did not run benchmarks; it is perceivable in everyday general Windows use and in applications. Storage Review describes the Raptor as "the fastest single-user desktop HDD" money can buy. To achieve its exceptionally fast seek performance, the Raptor has to move
the read/write heads across the surface of the disc with exceptional
speed. A side effect is that the seeks are sudden and sharp, not a good combination for
acoustic quality. The seeks are 4-5 dBA/1m higher than the idle noise, enough
to be plainly audible. The seek vibration is equally sharp; when placed
on our vibration box, the seeking drive produced a loud rumble that added
significantly to the overall noise level. Enabling AAM has little effect
on seek noise (or power dissipation). Careful listening revealed that the sharp clicks occurred
slightly less frequently with AAM, but neither noise character nor volume
changed significantly.

The vibration level at idle is quite good, on par with the Barracuda IV.
In a real system, the Raptor's vibration noise might be slightly more intrusive
than the Barracuda because of the higher pitch fundamental of the 10,000 RPM drive (167 Hz instead of 120 Hz for a 7200 RPM drive),
but the total amount of vibration is roughly
the same.

We were expecting that the higher spindle speed of the Raptor would translate
into a higher power draw. This did appear to be the case, although the increase
in power consumption was much less than we expected, somewhere in the realm
of 1W at idle and 2-3W while seeking. Despite its spindle speed, the Raptor
is not the most power hungry drive we've seen; it is merely higher than average.
With the extra heatsinks that are incorporated into the casing, it should
have no problem dissipating the extra heat that this power produces.

Caviar SE

After listening to the smooth idle of the Raptor, the Caviar SE sounds
bit coarse. In addition to airflow noise, a midband whine from the
drive motor is audible. The tonal nature of the noise makes it seem louder
than the 22 dBA/1m we measured. Additionally, our sample had a faint high-pitched
metallic squeal that faded in and out seemingly at random. Because we had only one sample. there no way to tell
whether the noise is representative of this model and/or the Caviar line as a whole. It could admittedly be specific to our sample.

Without AAM, the seek noise is loud. The character of the noise is not bad;
seeks sound dull and slightly damped. However, there is a slight metallic
ringing that is audible underneath the main seek noise. Unfortunately, the
6-8 dBA/1m rise above idle noise is too much for it to be considered quiet.
Enabling AAM (or, if you wish, Soft Seek) eliminates most of the seek noise; the repetitive clatter that is so characteristic of seek noise disappears
almost entirely. What remains is the odd metallic ringing that sounds as though
a thick chain is being dragged behind a (quiet) truck on a distant road. This
ringing noise may be related to the intermittent squeal that we noticed while
the drive was idling; although the rhythmic character of the noise is only
apparent during seeks, the approximate frequency and volume is about the same.
The volume with AAM enabled is quite quiet for seek noise, rising only a decibel
or two above idle noise.

As with the Raptor, the vibration is roughly the same as a Barracuda IV:
As good as any 3.5" drive, but still enough that it is worth suspending
the drive in a quiet system.

Oddly, Western Digital specifies the power consumption for the Caviar SE
higher than the Raptor. Our testing did not bear this out. The power
consumption of the Caviar is roughly in line with other drives we've tested, which have ranged
6~7W at idle and 8~12W during seek.

AUDIO RECORDINGS

Audio recordings were made of the drives and are presented here
in MP3 format. The first two recordings below contains ten seconds of idle noise,
followed by ten seconds of seek noise with AAM enabled and ten seconds more
with AAM disabled. Keep in mind that the audio recordings paint only part of
the acoustic picture; vibration noise is not recorded, and drives often sound
different depending on the angle from which they are heard.

Western
Digital Raptor WD740GD (Idle: 21 / AAM: 24-26 / Seek: 25-26 dBA/1m)

Western
Digital Caviar SE WD2500JD (Idle: 22 / AAM: 23-24 / Seek: 28-30 dBA/1m)


Recently Reviewed:

Maxtor
DiamondMax 10 6B300S0 (Idle: 23 / AAM: 24-25 / Seek: 27-28 dBA/1m)

Hitachi
Deskstar 7K250 HDS722525VLSA80 (Idle: 23 / AAM: 25 / Seek: 26 dBA/1m)

Reference Comparatives:

Seagate
Barracuda IV ST340016A (Idle: 20 / AAM: 23 / Seek: 25-26 dBA/1m)

Samsung
Spinpoint P80 SP0802N, Nidec Motor (Idle: 21 / AAM: 23-24 / Seek: 25-26 dBA/1m)

Samsung
Spinpoint P80 SP0802N, JVC Motor (Idle: 21 / AAM: 25 / Seek: 27 dBA/1m)

Nexus 92mm
case fan @ 5V (17 dBA/1m) Reference

HOW TO LISTEN & COMPARE

These recordings were made
with a high resolution studio quality digital recording system. The hard
drive was placed on soft foam to isolate the airborne noise that it produces;
recordings do not take into account the vibration noise that hard drives
produce. The microphone was centered 3" above the top face of the hard
drive. The ambient noise during most recordings is 18 dBA or lower.

To set the volume to a realistic level (similar to the
original), try playing the Nexus 92 fan reference recording and
setting the volume so that it is barely audible. Then don't reset the
volume and play the other sound files. Of course, tone controls or other
effects should all be turned off or set to neutral. For full details on
how to calibrate your sound system to get the most valid listening comparison,
please see the yellow text box entitled Listen to the Fans
on page four of the article
SPCR's Test / Sound Lab: A Short Tour.

CONCLUSIONS

Our first experience with the FDB-equipped WD Raptor has been a good one. The fastest single-user drive also turns out to be very quiet, at least while
idling. This is not to say that there is no sonic price to pay for a high performance
drive. The sudden seeks and ineffectiveness (or lack?) of the AAM implementation
are not characteristics of a truly quiet drive.

We would hesitate to recommend the Raptor if silence is the first priority.
However, those who see low noise as a secondary goal after pure performance should
be happy with the low noise of this drive, especially when it is not in seek or write.

The Caviar SE, on the other hand, was a bit disappointing on the subjective level. Still, it's
a huge improvement over Western Digital's
older drives, and it's quiet enough that inside a case, the differences between the Caviar SE
WD2500JD and a quieter drive may be inconsequential. The best thing about the Caviar is
undoubtedly its implementation of AAM, which made a bigger difference than with any other drive we've tried it on.

The metallic ringing during seek (and the intermittent squeal
during idle) is a sound we've never encountered in another drive. Assuming that
our sample is representative the rest of the line, this is a significant point
against the Caviar, as the combination of its infrequent nature and high frequency
is a recipe for an acoustic irritant. Keep in mind, however, that until a couple more Caviar samples can be examined, these comments must be limited to the sample on hand.

Many thanks to Western
Digital
for the Raptor and Caviar SE samples.

Discuss this article in the SPCR Forums.

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