• Home
  • blog
  • Seagate Momentus XT: The Best of Both Worlds?

Seagate Momentus XT: The Best of Both Worlds?

The Momentus XT 500GB is a hybrid notebook drive from Seagate featuring two 250GB platters spinning at 7200 RPM, 32MB of cache, and 4GB of SLC NAND flash memory. Is it truly an affordable high capacity drive with SSD-like performance?

Seagate Momentus XT 500GB: Hybrid Laptop Drive

September 12, 2010 by Lawrence Lee

Product
Seagate Momentus XT ST95005620AS
500GB 2.5" HDD
Sample Supplier
Street Price
US$130

It has often been said that the biggest bottleneck in modern computer systems
is the hard disk drive. Over time, hard drive interfaces have changed, areal
density has increased, and recording strategies have improved, but the inside
of a modern hard drive is essentially the same as one from decades past. Platters
are spun at high speed on a spindle with data being read and written using a
head attached to an actuator arm, a digital system operating in a method not
unlike the very analog vinyl record player.

Solid state storage was supposed to change all this — the promise of almost
instantaneous access to all your data was supposed to save the modern PC from
being dragged down by the aging sluggish mechanical hard drive. Unfortunately
this dream is still far from realized, bogged down at the moment by economics,
manufacturing limitations, and of course the high demand for flash memory in
other markets. As a result, the current crop of SSDs, though faster than HDDs,
are also many times more expensive per byte.



The Momentus XT 500GB.

As we wait for the solid state revolution to gain more traction, Seagate has
produced an interesting bastard child that may sate our current appetite for
fast but affordable storage. Momentus XT is a line of notebook drives from Seagate
with both physical disks and flash memory collaborating together. Available
in 250, 320, and 500GB varieties, they are essentially the first consumer hybrid
hard drives, part mechanical and part solid state.

Our sample is the 500GB part, affectionately referred to in enthusiast circles
by its model number: ST95005620AS. The physical portion of the drive consists
of two 250GB platters spinning at 7200 RPM with 32MB of cache. The solid state
portion of the drive is comprised of 4GB of solid state SLC NAND flash, a very
small capacity for a drive, but a huge amount for additional cache. The XT features
something called Adaptive Memory which decides which files get sent to NAND
flash for quicker retrieval based on what applications are used most frequently.
In theory what you do most on your PC will gradually speed up over time if you
use a Momentus XT.

Seagate Momentus XT: Key Features & Benefits
(from product
overview
)
FEATURE & BRIEF Our Comment
Solid state hybrid drive delivers SSD-like
performance with hard drive capacity options.
The performance claim seems over-hyped
but we can’t argue about capacity. SSDs in the same price range as the 500GB
Momentus XT hold 64GB at most.
Adaptive Memory™ technology customizes
performance by aligning to user needs for overall improved system response.
Makes sense in theory, but how much of
a difference can it really make in real life?
80 percent faster performance than traditional
7200-RPM drives in PCMark Vantage benchmark scores.
Basing speed on a single benchmark is
never a great idea.
Low heat and vibration—quiet operation
without giving up storage capacity and affordability.
There is no reason the Momentus XT should
be louder or quieter than the already fairly quiet Momentus 7200.4.
OS and application-independent — designed
for any SATA standard laptop PC.
Good.
Seagate® 5-Year Limited Warranty2 years longer than industry standard.

Seagate Momentus XT 500GB: Specifications
(from the product
data sheet
)
Model NumberST95005620AS
Capacity500GB
Cache32MB
InterfaceSATA 3Gb/s NCQ
Spindle Speed7,200 rpm
Weight110 grams (0.238 lb)
Power: Idle / Seek (Typical)0.8 W / 1.554 W
Acoustics: Idle / Seek (Typical)2.3 bels / 2.5 bels

TESTING

Our samples were tested according to our standard
hard drive testing methodology
. A significant change in our testing procedure is that as of mid-2008, we’re conducting most acoustics tests in our own 10~11 dBA anechoic chamber, which results in more accurate, lower SPL readings than before, especially as the SPL approaches 20 dBA and below, which is the territory of laptop drives. Our methodology focuses specifically on
noise, and great effort is taken to ensure it is comprehensively measured
and described. Performance is covered only lightly, for reasons discussed in detail in the methodology article.

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. Airborne acoustics are measured in our anechoic chamber using a lab reference
microphone and computer audio measurement system
. Measurements are taken at a distance of one meter from 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.

Summary of primary HDD testing tools:

Performance Test System:

Performance Test Tools:

Benchmark Details

  • COD5: Load time for "Downfall" level.
  • Far Cry 2: Load time for initial screen plus one level.
  • NOD32: Virus scan of 32 files/archives of varying size.
  • ExactFile: Creating a MD5 check file of our entire test suite folder.
  • TrueCrypt: Creating a 8GB encrypted file container.
  • 3DMark06: Install time, longest interval between prompts.
  • PowerDVD: Install time, longest interval between prompts.
  • Small File Copy: Copy time for 1,278 files ranging from 10KB to 4MB
    in size.
  • Large File Copy: Copy time for 4 files, 2 x 700MB and 2 x 1400MB
    in size.

A final caveat: As with most reviews, our comments
are relevant to the samples 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 time of testing were 10.5 dBA and 22°C.


Label.

PERFORMANCE

The Momentus XT with its unique properties, prompted us to develop a proper
hard drive test suite. Initially we tried using our standard system test suite
but this proved rather pointless as most of the results were the same regardless
of what drive was used (most consumer file archiving, audio and video encoding
applications are less hard drive dependent than we believed). Eventually we
settled on a mix of application, load, install, and copy times to give a good
sense of what to expect during real world use instead of the usual canned synthetic
benchmarks.

Our entire test suite was run start to finish 3 times on each drive with a
reboot and defragmentation in between runs for each drive except for SSDs and
the XT (defragmentation resets optimizations made to the XT’s flash memory).
The best times were collected for comparison.

Boot and application loading times are typically where users see the most gain
from having an SSD — the XT is certainly no disappointment in this department.
The boot time and loading times for two games, Call of Duty: World At War and
Far Cry 2, were better than a couple of 5400 RPM notebook drives as well as
a pair of desktop drives. While it had no trouble besting mechanical hard drives,
it fell well short of the Kingston SSDNow, a budget 64GB SSD.

Application performance was more like that of a mechanical hard drive, but
the XT was still impressive, edging out the Barracuda 7200.11 in total completion
time of three tests: creating an encrypted file container with TrueCrypt, creating
a checksum file with ExactFile, and anti-virus scanning with NOD32.

When copying files to itself, the XT was far less impressive, though it still
left the Scorpio Blue and Hitachi Travelstar 5K320 in its dust.

Timed installs of PowerDVD and 3DMark06 the XT’s speed was more sobering, just
a few seconds faster than the Scorpio Blue and a tad slower than the Samsung
EcoGreen.

Adaptive Memory Performance: Did It Learn?

To get a better idea of how well the drive learned with its Adaptive Memory
feature, we ran the XT through an additional 2 runs through our test suite.
While none of our individual benchmarks displayed continual improvement through
all 5 runs, performance as a whole did indeed generally get better with time;
the difference between the first and last run was 4.2%. However it should be
pointed out that the 4th run turned out to be the second slowest. It seems to
us that on occasion, the difference made by Adaptive Memory isn’t enough to
cancel out the random amount of variation that occurs doing timed benchmarks.

ACOUSTICS, VIBRATION & POWER

The Momentus XT is not only a very fast laptop hard drive, it’s also very quiet,
sharing similar acoustics to its fully mechanical brother. It measured about
half a decibel lower than the Momentus
7200.4
, 13~14 dBA idle and 14~15 dBA when seeking, essentially the same
given sample variation and margin of error. It has a touch of whine but its
seeks are muted and innocuous.



The rotation of the platters causes a low frequency 120 Hz spike, while
seeking creates mostly high frequency noise at 3~5 KHz.

The Momentus XT also exhibits a similar, moderate level of vibration as the
7200.4, scoring a 7 on our subjective scale. It’s not particularly bad for a
laptop drive but there are a few 5400 RPM models that are noticeably superior
in this regard like the Momentus 5400.6 and Hitachi 5K500.B.

500GB NOTEBOOK DRIVES
HDD
Mfg date
firmware version
Vibration
1-10
(10 = no vibration)
Activity State

Airborne Acoustics
(dBA@1m)

Measured
Power

Seagate Momentus
XT 500GB
ST95005620AS
June 2010
firmware SD22
10
Sleep
11
0.55 W
7
Idle
13~14
1.34 W (1.16 W heads unloaded)
Seek
14~15
2.08 W
Hitachi Travelstar 5K500.B 500GB
February 2009
firmware PB4OC60G
8
Idle
14
0.7W (0.6 W heads unloaded)
Seek
15
2.2 W
Seagate Momentus 7200.4 500GB ST9500420AS
March 2009
firmware 002SDM1
7
Idle
14
1.1 W (0.9 W heads unloaded)
Seek
15
2.35 W
Seagate Momentus 5400.6 500GB ST9500325ASG
February 2009
firmware 0001SDM1
8
Idle
16
0.8 W (0.65 W heads unloaded)
Seek
18
2.2 W

While it has similar acoustics and vibration levels as the 7200.4, it’s idle
power consumption is poor by modern standards — we haven’t seen 1.3 W idle
from a laptop drive in 4~5 years. In addition, the drive needs to sit idle for
about 30 seconds before the head parks, 3~4 times longer than most notebook
drives, making its overall idle power even worse. After about 50 seconds the
mechanical portion of the drive shuts down completely, but only when used as
a secondary data drive — we did not experience this when running Windows
on it. When seeking, the advantage swings the other way with the XT being more
frugal by 0.27 W.

DRIVE COMPARISON

Like the Momentus 7200.4, the Momentus XT is one of the quietest notebook hard
drive we’ve tested, though its power consumption is disappointing.

ALL DRIVES TESTED IN ANECHOIC CHAMBER
Drive
Mfg date
firmware version
Vibration
1-10
(10 = no vibration)
Activity State

Airborne Acoustics
(dBA@1m)

Measured
Power

SOLID STATE DRIVES
Kingston SSDNow V 30GB
10
Idle
10~11
0.20 W
Seek
1.40 W
OCZ Vertex 30GB
10
Idle
10~11
0.40 W
Seek
1.26 W
Intel X25-M G1 80GB
10
Idle
10~11
0.56 W
Seek
2.15 W
Kingston SSDNow V Gen II 64GB
10
Idle
10~11
1.03 W
Seek
2.95 W
NOTEBOOK DRIVES
Hitachi Travelstar 5K320-250 250GB
May 2009
firmware FBE0C40C
8
Idle
13
1.08 W (0.85 W heads unloaded)
Seek
13~14
2.15 W
Seagate Momentus
XT 500GB
ST95005620AS
June 2010
firmware SD22
7
Idle
13~14
1.34 W (1.16 W heads unloaded)
Seek
14~15
2.08 W
Hitachi Travelstar 5K500.B 500GB
February 2009
firmware PB4OC60G
8
Idle
14
0.7 W (0.6 W heads unloaded)
Seek
15
2.2 W
Seagate Momentus 7200.4 500GB ST9500420AS
March 2009
firmware 0002SDM1
7
Idle
14
1.1 W (0.9 W heads unloaded)
Seek
15
2.35 W
Seagate Momentus 5400.6 500GB ST9500325ASG
February 2009
firmware 0001SDM1
8
Idle
16
0.8 W (0.65 W heads unloaded)
Seek
18
2.2 W
WD Scorpio Blue 500GB WD5000BEVT
September 2008
firmware 01.01A01
7
Idle
15
0.95 W (0.8 W heads unloaded)
Seek
16
2.5 W
WD Scorpio Blue 640GB WD6400BEVT
September 2009
firmware 01.01A01
7
Idle
15~16
0.87 W (0.74 W heads unloaded)
Seek
16
1.95 W
"GREEN" DESKTOP DRIVES
WD Caviar Green
1.5TB WD15EADS
November 2009
firmware 01.00A01
9
Idle
13
4.5 W
(2.8 W heads unloaded)
Seek (AAM)
14
5.8 W
Seek
Seagate Pipeline HD .2 500GB ST3500414CS
March 2009
firmware SC13
8
Idle
13
2.7 W
Seek
14
6.7 W
Samsung F2 EcoGreen 500GB HD502HI
February 2009
firmware 1AG01114
8
Idle
12
3.2 W
Seek (AAM)
15
5.3 W
Seek
16
6.1 W
WD Caviar Green
2TB WD20EADS

February 2009
firmware 01.00A01
7
Idle
13
6.4 W (4.0W heads unloaded)
Seek (AAM)
6.5 W
Seek
13~14
6.5 W
Seagate Pipeline HD .2 1TB ST31000424CS
April 2009
firmware SC13
7
Idle
12
4.3 W
Seek
16
7.3 W
Seagate Pipeline HD
500GB ST3500321CS

July 2008
firmware SC14
6
Idle
14
4.1 W
Seek
15
6.9 W
Seagate Barracuda LP 2TB ST32000542AS
June 2009
firmware CC32
6
Idle
14
4.7W
Seek
17
7.9W
Samsung EcoGreen F3
2TB HD203WI
May 2010
firmware 1AN10003
7
Idle
15~16
4.7 W
Seek (AAM)
17~18
6.1W
Seek
18~19
6.9 W

AUDIO RECORDINGS

These recordings were made with a high resolution, lab quality, digital recording
system inside SPCR’s own 11
dBA ambient anechoic chamber
, then converted to LAME 128kbps encoded MP3s.
We’ve listened long and hard to ensure there is no audible degradation from
the original WAV files to these MP3s. They represent a quick snapshot of what
we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!

The recordings start with 5 to 10 seconds of ambient noise, then 10 second
segments of the drive in the following states: idle, seek with AAM enabled (if
applicable), and seek with AAM disabled.

Comparatives:

CONCLUSIONS

The Seagate Momentus XT 500GB is an interesting integration of
flash and mechanical storage. It is certainly a very fast drive, but it in most
cases its performance is closer to that of a traditional 7200 RPM hard drive
than a solid state drive. As for its Adaptive Memory technology, we did see
an improvement of about 4% between our 1st test run and our 5th, so it does
seem that the drive does a fair job optimizing what is stored on the flash portion
of the drive over time. It’s a nice little boost but we can’t say how well it
holds up over longer periods of time or more varied usage.

While the drive isn’t silent like a SSD, its airborne acoustics
are excellent for notebook drive in general, not just a 7200 RPM model. We’re
not sure exactly what Seagate is doing to make their 7200 RPM Momentus drives
so quiet, but we hope they keep at it. The other factor that affects noise is
vibration, and in this regard the XT is about average.

The last thing to consider is power consumption, something that
is obviously paramount for notebook battery life. The XT takes a long time for
its head to park, and its idle power usage is on the high side, almost twice
that of the Hitachi
Travelstar 5K500.B
for example. Upgrading from a low power 5400 RPM
drive could result in a loss of ~5% or more in idle run time if you have a fairly
energy efficient laptop.

Ultimately the Momentus XT is no replacement for a SSD, but it
is undoubtedly the fastest drive with spinning platters you can buy for your
laptop. It’s a fair compromise as the 500GB XT has almost 8 times more capacity
than an equivalently priced SSD. If you want the speediest drive available for
your notebook without sacrificing capacity or spending a small fortune, the
Momentus XT is really the only choice. Just keep in mind you may experience
a small reduction in battery life in compensation.

Many thanks to Seagate
and Momentus XT sample.


The Seagate Momentus XT is Recommended by SPCR.

* * *

SPCR Articles of Related Interest:
SPCR’s Hard Drive Testing
Methodology

SPCR’s Recommended Hard Drives

Samsung 2TB EcoGreen
F3 Hard Drive

Western
Digital Green 1.5TB vs. Seagate 7200.12 500GB

More
500GB notebook drives: Seagate 7200.4 & Hitachi 5K500.B

5900rpm
Seagate Hard Drives: Barracuda LP, Pipeline HD .2

* * *

Discuss
this article in the SPCR Forums

Leave a Comment

Your email address will not be published. Required fields are marked *