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Hitachi TravelStar E7K100 7.2k-rpm notebook drive

January 30, 2006 by Devon
Cooke

Product
Hitachi TravelStar E7K100 HTE721010G9SA00

100GB, 7,200 RPM Notebook drive
Manufacturer
Market Price
~US$200-300

It's well known that notebook drives have acoustic and thermal advantages over conventional 3.5" desktop drives, but not everyone is willing to accept the somewhat slower performance and questions about longevity that come as part of the deal. Other disadvantages include mounting issues, availability, and cost, but these problems have more to do with supply and demand than an inherent problem with the notebook form factor.

Eventually, all of these obstacles will be overcome as the industry transitions
to the 2.5" form factor even for desktop drives. Leading the way
is Hitachi Global Storage with the E7K100, a 100GB notebook drive that spins
at 7,200 RPM and is "designed for demanding applications requiring extended
power-on usage". Obviously, not all of the disadvantages have been addressed,
but the E7K100 does address the performance concerns, which is really all Hitachi
has control over.

The E7K100 and its cousin, the 7K100, represents the second generation
of 7,200 RPM notebook drives from Hitachi. This gives Hitachi an advantage:
No other company has been making 7,200 RPM notebook drives for as long. Currently,
Seagate is the only other major player with a 7,200 RPM notebook drive on the
market; we reviewed the Momentus
7200.1 a couple months ago
. Our impressions of this drive were mixed. Its
noise characteristics seemed to combine desktop and notebook qualities, so although
it was quieter than any desktop drive, it wasn't as quiet as most slower 5,400 RPM notebook drives.

Keeping that in mind, can the E7K100 be as quiet the
rest of the notebook drives, or does it suffer the increase in noise as the
Seagate?

HITACHI TRAVELSTAR E7K100 HTE721010G9SA00 (quoted
from Hitachi's
web
site
)
FEATURE & BRIEF COMMENT
100GB maximum capacity
Still quite a bit for a notebook drive, but no longer the most available.
Second generation enhanced availability 7200 RPM hard drive
Enhanced
availability? They're certainly not talking about retail here...
Designed
for demanding applications
requiring extended power-on usage
For example,
one of the recommended applications is a blade server.
Desktop-like performance with mobile drive benefits
7,200 RPM
in a notebook form factor. Quiet? We'll see.
Supports both Parallel & Serial ATA 1.5Gb/s interfaces
PATA is still
the dominant interface for notebooks.
RoHS compliant
Lead free.

Hitachi's lineup of notebook drives is a little confusing because there are
two different model lines, the 7K100 and the E7K100, without any obvious
differences between the two. The marketing material for the two lines positions
the 7K100 as a performance drive for notebooks, while E7K100 is targeted more
at applications where drives are needed in constant, long-term operation, like
servers and integrated electronics. Yet the two models seem to be nearly identical.
The promotional
photos for the two drives
are identical, which suggests that whatever the
difference is, it must be implemented in firmware or software, not hardware.

A detailed comparison of the engineering specifications for the two drives
(7K100,
E7K100)
revealed exactly two differences:

  1. The 7K100 implements several power saving modes that are not present in
    the E7K100.
  2. The operating temperature is 40°C for the E7K100, and 55°C for the
    7K100.

Of these, only the first constitutes are real difference. Changing the maximum
operating temperature is just a way to guarantee better reliability within the
rated specs. It is extremely difficult to believe that the hardware is identical
in every regard except heat tolerance.

So, why should the elimination of low power modes lead to better suitability
for server applications? We were able to make an educated guess based our knowledge
of drive mechanics and Hitachi's
description of what the power modes do
.

First of all, low power is only a real concern for drives that are powered
from a battery. Lower power consumption is generally achieved by turning off
one or more features of the drive when it is not actively reading or writing.
But, this means that there is a slight delay when the drive is needed while
the various features turn back on. As a general rule, the more power is saved,
the longer it takes to bring the drive back to its active state. Thus, performance
takes a slight hit when the drive is coming out of one of its low power modes.

The amount of power saved is not large — generally less than one watt
— so these power saving modes have no advantage in a system that does
not use a battery. It therefore makes sense to disable the low power modes in
drives that will not be used in notebook applications.

In addition to causing a little extra latency when the drive starts seeking,
some of the low power modes also cause mechanical stress on the internal components.
This is probably the main reason why the E7K100 ships without the low power
modes.

For example, most notebook drives unload the heads to save power within a few
seconds once they becomes idle. In a server environment, there are seeks every
few seconds, which could easily lead to a situation where frequently and unnecessarily
being loaded and unloaded. In addition to the effect this would have on performance,
it could also cause the drive to fail prematurely. Both the 7K100 and the E7K100
are rated for 600,000 load/unload cycles. In a system where the heads are loaded
and unloaded every 10 seconds (a possibility in a server), the drive would exceed
this number of cycles in just 70 days — just over two months.

Other power saving modes could also affect the lifetime of the drive. Rapid
cycling of the power to the circuit board could eventually lead to the failure
of the logic board, and repeatedly spinning the disc up to speed stresses the
spindle and the power supply.

Even if the lack of power management is the only difference between the 7K100
and the E7K100, the E7K100 is clearly a more reliable choice for a desktop or
server system.



The SATA interface makes it compatible with a desktop system without an adapter.

SPECIFICATIONS

The specifications below are specific to model 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.


Specifications: Hitachi TravelStar E7K100 HTE721010G9SA00
Capacity
100 GB
Cache
7538 KB
Platters
2
Heads
4
Spindle Rotation Speed
7,200 RPM
Interface
SATA 1.5 Gb/s
Latency
4.2 ms
Average Seek
10 ms (read) / 11ms (write)
Media Transfer Rate
629 Mbits / second
Weight
115 g
Operating Temperature
5 - 40°C
Power Dissipation: Idle / Seek
2.1 / 2.7 W
Acoustics: Idle / Seek
2.6 / 3.0 Bels

The E7K100 is nominally listed as having an 8 MB cache. This is not
quite the case. While there is indeed 8MB of memory on the logic board, 418
KB are reserved for the drive's firmware, which leave approximately 7.5 MB left
for the cache. The impact on drive performance will vary with usage, but should
be very slight. Because of the way caches are implemented, the difference will
typically be much less than the ~7% difference in cache size.

That aside, the specifications look similar to the Seagate Momentus 7200.1:
Average seek is significantly faster than notebook drives with slower spindle
speeds, but not quite on pace with most desktop drives. Power
dissipation and noise are both slightly higher than usual.

As mentioned, the 40°C operating temperature for this drive is very low,
but probably represents the tighter tolerances that are expected of server equipment
than an inherent part of the drive's design. Most notebook drives are rated
for either 55°C or 60°C.

TEST RESULTS

Our sample was tested according to our standard
hard drive testing methodology
. Our methodology focuses specifically on
HDD 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.

The E7K100 was compared against our reference notebook drive,
Samsung MP0402H, that we profiled in a recent
notebook drive review
. It was also compared against the Seagate Momentus
7200.1.

Two forms of hard drive noise are measured:

  1. Airborne acoustics
  2. Vibration-induced noise.

These two 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. 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.

A final caveat: As with most reviews, our comments
are relevant to the sample we tested. Your sample may not be identical. There
are always some sample variances, and manufacturers also make changes without
telling everyone.

Ambient conditions at the time of testing were 18 dBA and 22°C.

NOTEBOOK DRIVE NOISE EVALUATION
Drive

Mfg date

firmware version
Vibration

1-10

(10 = no vibration)
Activity State

Airborne Acoustics

Measured Power
Hitachi TravelStar E7K100

October 2005

firmware MCZOC10HZO
8
Idle

20 [email protected]

1.5 W
Seek (AAM)

21 [email protected]

3.8 W
Seek (Normal)

21-22 [email protected]

3.9 W
Samsung MP0402H

April 2004

firmware UC100-10
8
Idle

17 [email protected]

0.8 W
Seek (AAM)

18 [email protected]

2.3 W
Seek (Normal)

19-20 [email protected]

2.4 W
Seagate Momentus 7200.1 ST910021AS

Date Code: 06101

firmware 3.04
8
Idle

21 [email protected]

1.7 W (heads unloaded)

2.9W (heads loaded)
Seek (Normal)

22-23 [email protected]

3.7 W

Unlike the Momentus 7200.1, the idle noise for the E7K100 was fairly typical
of a notebook drive. The bulk of the noise was a slightly hollow-sounding whoosh
that should easily fade into the residual fan noise of a quiet system. There
was also a slight hum, but it was inaudible beyond about eight inches from the
drive. In comparison to the Samsung reference drive, the E7K100 is clearly louder,
but it is certainly no worse than most other notebook drives.

Even better, seeks with AAM enabled were virtually inaudible... and AAM comes
enabled by default. In fact, they were so quiet that extra care had to be taken
when making the MP3 recordings, since it was not obvious when the drive was
seeking. It should be noted that the measured noise level for AAM is a little
misleading in this respect; subjectively, no difference between idle and AAM
seek could be heard except within six inches of the drive.

The measurements are also misleading about the difference between AAM and normal
seeks. Even though the measured difference was only a single decibel, the subjective
difference was significant: Seeks could be heard clearly in normal mode. Seek
noise was characterized by a rapid ticking, much like the sound of cold drainpipes
cracking (quietly) when a bath is suddenly emptied.

The level of vibration was about the same as both the 7200.1 and the MP0402H.
However, the Hitachi shares a flaw with the Seagate here: Because the drives
spin at 7,200 RPM, the resonant frequency is higher, and therefore easier to
hear. For this reason, the E7K100 will benefit more from soft-mounting than
most other notebook drives.

As mentioned, power management is disabled on the E7K100, so APM was not selectable
from the Hitachi Feature tool. Even so, power consumption at idle was about
average for a notebook drive and better than the Seagate Momentus 7200.1. Power usage for
seeks, on the other hand, was higher. In fact, the E7K100 draws more
power than any other notebook drive we've tested when seeking, beating out the
7200.1 by a small (perhaps negligible) margin. Surprisingly, there was very
little difference in the power draw between AAM and normal seeks.

2.5" HDD NOISE COMPARISON
Drive Model

(linked to review)
SPL

Idle / AAM / Seek

([email protected])
Vibration

1-10

(10 = no vibration)
UNIT UNDER REVIEW:

Hitachi TravelStar E7K100

HTE721010G9SA00
20 / 21 / 21-22
8
Hitachi's flagship 7,200 RPM notebook drive,
competing directly with the Seagate Momentus 7200.1, and beating it handily
in terms of both noise and idle power consumption. Power management is
disabled, as the drive is targeted at the server and workstation segments,
where low power is not a requirement. Unfortunately, the high rotation
speed causes a lot of vibration, which resonates at the relatively high
(and audible) pitch of 120 Hz.
Seagate
Momentus 7200.1

ST910021AS
21 / – / 22-23
8
Seagate's performance-oriented notebook drive,
with a 7,200 RPM spindle speed that translates into a seek time that approaches
desktop performance. Unfortunately, the faster spindle speed causes corresponding
increases in turbulence noise (at idle) and power consumption. Subjective
noise quality is good for both seeks and idle, but the level of noise
is closer to desktop drives than the super quiet Samsung MP0402H. Vibration
resonance is at 120 Hz rather than the usual 90 Hz for notebook drives.
Seagate
Momentus 5400.2

ST9120821AS
20 / – / 20-21
9
Too close to the Samsung
MP0402H to crown either drive as low noise champion, but a very good choice
in any case. Idle noise has slightly more "wind noise" than the Samsung
but no high frequency noise at all. Although AAM is not supported, seeks
are completely inaudible when placed on soft foam. Consumes more power
than most notebook drives.
Western
Digital Scorpio
20 / 21 / 21
7-9
Sample variance makes it hard to rank the noise
this drive, but it belongs somewhere between the Samsung notebook series
and the Seagate Barracuda IV. Idle noise is mainly a low frequency motor
hum with little high frequency whine. Seeks are almost too quiet to notice,
and can be characterized as a low rumble. AAM has not effect, but it would
be hard to improve the seeks anyway. Vibration ranged from the level of
the Barracuda IV to below the Samsung MP0402H.
Fujitsu
MHT2080BH
22 / 23-24 / 23-24
9
Idle noise is rather disappointing;
it sounds undamped and is louder than the Barracuda IV. Seeks are about
average for a notebook drive, rising about 1-2 dBA/1m above idle. The
Fujitsu has the lowest vibration of any drive tested. May avoid the intermittent
clicking problem common with notebook drives because it waits for 10-15
seconds after a seek before unloading the heads. Consumes ~0.2W more than
other notebook drives in all power states.
17 / 18 / 19-20
8
The acoustics of this drive are virtually identical
to the Fujitsu MHT2040AT, a considerably slower 4200 rpm drive and the
quietest we've encountered. The Samsung is extremely quiet, and there
is very little if any high frequency noise to speak of. It has minimal
vibration, but placing it on soft foam does reduce low freq. noise audibly.
The unit used in the test PC was suspended in elastic string and mostly
surrounded by soft but dense foam. Seek noise is somewhat more audible
than the 1 dBA gain suggests, but very soft.
19 / – / 20
?
The Hitachi comes very close
to the Samsung, but has a slightly sharper and higher pitched sound, with
perhaps a touch more vibration as well. The seek noise is a touch louder
too. When inside even a very quiet desktop PC, the slightly higher noise
level of this drive over the Samsung may not be audible. The performance
is superior, according to SiSoftware Sandra 2005, and also subjectively.
Toshiba
MK6022GAX
22 / – / –
?
Slightly louder than the Seagate Barracuda
IV single platter 3.5" reference hard drive. The noise signature has the
broadband shhhh quality exhibited by the Samsung SP 3.5"
drives, but higher in pitch, a bit like the Seagate. A trace of whine,
but not like the Seagate Momentus. Seek noise is only moderately louder
than idle, perhaps by 3 dBA. Vibration is higher than any of the 4200rpm
drives; similar to the Momentus. Performance seems quite speedy, as it
should be with 16 MB cache and 5400rpm, but inconsistent results with
all the benchmarks tried stops me from publishing results.
Seagate
Momentus ST94811A
24 / – / –
?
The Momentus has a terrible
constant "pure" tone somewhere in the 6~10KHz range. It drops 2-3 dBA
in level when the listener or the mic faces the edge of the drive because
of directionality of the high frequency whine. Seek noise is substantially
higher, probably 3~5 dBA. Vibration is much lower than any 3.5" drive,
but higher than either of the 4200rpm drives tried. A real disappointment,
but it did perform about as fast as or faster than the Seagate Barracuda-IV.
Fujitsu
MHT2040AT
16 / – / –
?
The only noise maker in the Mappit
A4F
PC, which seemed virtually inaudible to me. The noise is not
inaudible, but very low and soft, easily dismissed in the ambient noise
of all but the quietest spaces. There is no high pitched whine to speak
of, and the seek noise does not seem more than maybe 2 dBA higher than
idle. It is the slowest performer of all the drives here. Extremely low
vibration.
Toshiba
MK4025GAS
16 / – / –
?
This 8 MB cache 4200 RPM
drive offers better performance than 2 MB cache 4200 rpm drives, and it
is identical in both idle and seek noise to the Fujitsu above. Extremely
low vibration.
RETIRED REFERENCE HDDs
Seagate
Barracuda IV ST340016A
21 / 23 / 25-26
6
In idle, it remains the quietest
of all 3.5" drives. This sample is almost 2 years old, but seems unchanged
in noise. There may be a touch of high frequency whine but it is very
low in level, and easily obscured when mounted in a PC case. Seek is considerably
higher, possibly as much as 5~6 dBA. Low vibration, but much higher than
any of the notebook drives.
Samsung
SP0802N (Nidec motor)
21 / 23-24 / 25-26
4
The idle noise is a touch higher,
and its seek may actually be lower than the Seagate B-IV. Similar vibration
level as the B-IV, but there are reports of some samples exhibiting much
higher vibration levels. This is cured by HDD decouple mounting (suspension
in elastic material or placement on soft foam), which is virtually mandatory
for a truly quiet PC anyway.

AUDIO RECORDINGS

Audio recordings were made of the drives and are presented here
in MP3 format. The 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.

Please note: This recording was made correctly. If you can't hear
a difference between idle and AAM seek, it's because the difference is too small!

Hitachi
TravelStar E7K100 HTE721010G9SA00 (Idle: 20 / AAM: 21 / Seek: 21-22 [email protected])

Reference Comparatives:

Seagate
Momentus 7200.1 ST910021AS (Idle: 21 / Seek: 22-23 [email protected])

Seagate
Momentus 5400.2 ST9120821AS (Idle: 20 / Seek: 20-21 [email protected])

Samsung
MP0402H (Idle: 17 / AAM: 18 / Seek: 19-20 [email protected])

Western
Digital Scorpio WD800VE (Idle: 20 / AAM: 21 / Seek: 21 [email protected])

Nexus 92mm
case fan @ 5V (17 [email protected]) 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

The E7K100 represents one of the best compromises between drive
performance and noise that we've seen. The noise level is the same as most other
notebook drives: Inaudible except to the extremely sensitive and/or picky. Even
better, drive performance should be on par with most desktop drives; both rotation
speed and areal density are similar. Not only that, the drive is targeted at
the server and workstation markets, so power management (and the associated
performance and longevity issues) should not be an issue. The E7K100 has the acoustic
advantage of a notebook drive without the usual disadvantages.

Thanks to all of the above, the E7K100 is well positioned to lead
the upcoming transition to 2.5" drives. That's not to say it doesn't have drawbacks, but most of the drawbacks are a matter of circumstance and convention
rather than any inherent flaws in the design.

As with any new technology, the E7K100 costs an arm and a leg, and it is difficult to find. Large OEMs
should not have a problem of course, but pickings are pretty slim from the retail
side. In fact, at the time of writing, I was unable to find any online stores
that carry the specific model reviewed here. However, several sites had lower
capacity models, and several had the 7K100 (no "E") with a 100 GB
capacity. Given the similarity between the two models,
the non-"E" version could easily be substituted with APM was disabled.

In spite of its advantages, the E7K100 is unlikely to become a
smash hit among desktop PC users — it simply costs too much. Until it comes down in price, it
will most likely remain a rosy indicator of good things to come.

Many thanks to Hitachi
Global Storage Technology
for the TravelStar E7K100 sample.

Discuss this article in the SPCR Forums.

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