Seagate Momentus XT 500GB Hybrid Hard Drive Review

[AkG]

For every consumer who wants the power and speed that only an SSD can provide, there are legions of others that just can’t afford or simply don’t need leading edge performance. However, there are plenty of people out there who want great performance coupled with sufficient storage capacity in a small form factor. For this niche, Seagate has really thought outside the box to create the Seagate Momentus XT 500GB hybrid hard drive.

The Momentus XT line is designed to combine the speed of an SSD with the capacity standard hard drives bring to the table. Seagate was able to do all this by taking their standard Momentus “7200.4”, 7200 RPM hard drive and placing 4GB worth of SLC NAND on it. While 4GB doesn’t sound like much, the Momentus XT is smart enough to learn your usage pattern and only place the most used files on this high speed storage. By only using 4GB of SLC for this onboard “cache”, pricing could be kept under $120 while still providing tangible benefits.

This isn’t the first time Seagate has tried this hybrid approach, but it really does sound like the first time where it may work quite well. Especially for laptop users who want to upgrade from their glacially slow 5400 RPM drives.

The XT series is obviously not going to be able to outperform today’s flagship Solid State Drives but it is not really meant to either. To test whether or not the Momentus XT can compete in this storage niche, we will not only be testing it to some of the more popular 7200 RPM and 5400 RPM 2.5” hard drives, but also against a couple of Solid State Drives that are in a similar price range as it.

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[AkG]

Specifications

Specifications

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[AkG]

Adaptive Memory Technology Explained

Adaptive Memory Technology Explained

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As mentioned in the introduction, the Seagate Momentus XT is not your typical 2.5” 7200 RPM drive since it comes with 4GB of SLC NAND in addition to the usual platters. More importantly, this unique design is what allows Seagate to claim some impressive performance numbers for the XT.

Typically, Single Layer Cell NAND is much more robust than its MLC counterpart and is good for about 100,000 write cycles. However, since there is so little of it, under normal circumstances the cells themselves would be worn down very quickly. Luckily, Seagate came up with the same answer Silverstone did for their HDDBoost: have the NAND used primarily for read operations while writing to it as infrequently as possible.

Silverstone took the approach of simply copying the first few sectors of the hard drive to the attached SSD and calling it a day. Stick in a bigger SSD and more would get copied. This is all well and fine when you have complete control over the size of the NAND used but when only 4GB of non-upgradable space is on tap such an approach simply isn’t practical. Copying the data over blindly on start-up is another approach which has been used but once again, it is an inelegant solution to a complex problem and wouldn’t help performance all that much.

To get around the size limitation and actually make this hybrid design live up to its potential, Seagate created a number of adaptive algorithms which learn over time exactly what files you access frequently and copy only those over to the onboard NAND. As your needs change, so too would the files copied to the NAND flash. Seagate calls these algorithms “Adaptive Memory Technology”.

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In its most basic form, the 4GB of NAND flash memory acts as a large yet smart non-volatile cache buffer which can store the most-used files even after reboots. This harnesses all the read speed performance offered by flash memory but since it is only the most accessed files writes which are accessed, this drive should have a long, long life.

The downside to Adaptive Memory Technology is its lack of the write speed boosts that flash memory has is famous for. In addition, since the XT only has 4GB of NAND, it really doesn’t hold all that much data when compared to the drive’s total capacity of 500GB.

 

[AkG]

A Closer Look at the Seagate Momentus XT

A Closer Look at the Seagate Momentus XT

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Upon first glance the Seagate Momentus XT 500GB looks like your typical 2.5” hard disk drive. In fact there are no real clues to say that the XT is any different than the non hybrid models Seagate makes. The bottom of the XT may have an overly long PCB, but then again many 2.5” “laptop” drives have nearly full length PCBs and it really doesn’t look out of place. More to the point there are no chips, nor other items on the bottom of the PCB, as they are all sandwiched in between the PCB and the bottom of the metal chassis.

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The Seagate Momentus XT 500GB has a max power draw of .58 of an amp of the 5volt line (as it is a 2.5” drive, it doesn’t use the 12V rail at all). This 2.9 watts of consumption is actually the same amount listed on our Western Digital Scorpio Black 250GB drive and really is par for the course for 7200 RPM 2.5” hard drives.

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Unlike a “normal” hard drive PCB which has spindle chip, main controller and maybe an external ram chip, the Seagate Momentus XT 500GB has a trio of primary chips along with a couple more. The largest of these is the Micron 4GB SLC NAND module.

To help control the NAND, Seagate has opted for a custom solution fabricated for them by eASIC. Unfortunately, neither company is particularly forthcoming about what this chip does but it is pretty obvious it most likely controls the Adaptive Memory Technology algorithms and by extension what is written to and read from the Micron Flash chip.

 

[AkG]

Testing Methodology

Testing Methodology

Testing a drive is not as simple as putting together a bunch of files, dragging them onto folder on the drive in Windows and using a stopwatch to time how long the transfer takes. Rather, there are factors such as read / write speed and data burst speed to take into account. There is also the SATA controller on your motherboard and how well it works with SSDs & HDDs to think about as well. For best results you really need a dedicated hardware RAID controller w/ dedicated RAM for drives to shine. Unfortunately, most people do not have the time, inclination or monetary funds to do this. For this reason our testbed will be a more standard motherboard with no mods or high end gear added to it. This is to help replicate what you the end user’s experience will be like.

Even when the hardware issues are taken care of the software itself will have a negative or positive impact on the results. As with the hardware end of things, to obtain the absolute best results you do need to tweak your OS setup; however, just like with the hardware solution most people are not going to do this. For this reason our standard OS setup is used. However, except for the Vista load test times we have done our best to eliminate this issue by having the drive tested as a secondary drive. With the main drive being a Phoneix Pro 120GB Solid State Drive.

For synthetic tests we used a combination of the ATTO Disk Benchmark, HDTach, HD Tune, Crystal Disk Benchmark, IOMeter, AS-SSD and PCMark Vanatage.

For real world benchmarks we timed how long a single 10GB rar file took to copy to and then from the devices. We also used 10gb of small files (from 100kb to 200MB) with a total 12,000 files in 400 subfolders.


For all testing a Gigabyte GA-890FXA-UD5 motherboard was used, running Windows 7 64bit Ultimate edition.

All tests were run 4 times and average results are represented.

In between each test suite runs (with the exception being IOMeter which was done after every run) the drives are cleaned with either HDDerase, SaniErase or OCZ SSDToolbox and then quick formated to make sure that they were in optimum condition for the next test suite.


Processor: 1090T @ 3.3 GHZ (turbo core set to 3.8GHZ)
Motherboard: Gigabyte GA-890FXA-UD5
Memory: 16GB Mushkin DDR3 1300
Graphics card: Asus 580GTX
Hard Drive: 1x G.Skill Phoneix Pro, 1x Seagate 3TB XT
Power Supply: XFX 850


SSD FIRMWARE (unless otherwise noted):

OCZ Vertex: 1.6
Kingston SSDNow V+ 128GB: AGYA0201
OCZ Vertex 2: 1.24 (custom “full speed” SandForce 3.4.x firmware)
G.Skill Phoenix: 305 (standard “mass production” firmware)
Patriot Inferno: 305 (standard “mass production” firmware)
OWC Mercury Extreme Pro: 310 (standard 3.1.0 firmware)
Corsair Force F120: 2.0 (aka standard 3.4.0 firmware)
Mushkin Callisto Deluxe 40GB: 340A13F0 (custom full speed 3.4.0 firmware)
Seagate Momentus XT 500GB Hybrid: SD24


Please Note: For the Seagate Momentus XT 500GB drive, unlike our usual 4 runs, we ran all tests 4 times as a warm up and then started testing with another 4 runs.

 

[AkG]

Read Bandwidth / Write Performance

Read Bandwidth

For this benchmark, HDTach was used. It shows the potential read speed which you are likely to experience with these hard drives. The long test was run to give a slightly more accurate picture. We don’t put much stock in Burst speed readings and thus we no longer included it. The most important number is the Average Speed number. This number will tell you what to expect from a given drive in normal, day to day operations. The higher the average the faster your entire system will seem.

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As you can see, the Momentus XT 500GB really posts some downright impressive sequential read performance numbers. It dominates the 7200 RPM 2.5” drives and even beats the 10,000 RPM HLFS VelociRaptor. With that being said it does lose and lose badly to Solid State Drives, but the difference is not as big as it “should” be. For all intents and purposes the XT is faster than literally any hard drive out there and can give comparably priced SSDs a real run for their money.

Write Performance

For this benchmark HD Tune Pro was used. To run the write benchmark on a drive, you must first remove all partitions from that drive and then and only then will it allow you to run this test. Unlike some other benchmarking utilities the HD Tune Pro writes across the full area of the drive, thus it easily shows any weakness a drive may have.

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As expected, the write performance of the Momentus XT 500GB is decent for a 7200 RPM2.5” hard drive but it does suffer without that 4GB of NAND to boost its performance. Unlike the read speeds it can not match let alone beat even a VelociRaptor let alone an “entry level” Solid State Drive.

 

[AkG]

Crystal DiskMark / PCMark Vantage

Crystal DiskMark

Crystal DiskMark is designed to quickly test the performance of your hard drives. Currently, the program allows to measure sequential and random read/write speeds; and allows you to set the number of tests iterations to run. We left the number of tests at 5 and size at 100MB.

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Once again, the writes are decent for a 7200 RPM laptop drive but not particularly spectacular. It is surprising to see that the reads are not anywhere close to what they “should” be if the NAND was kicking in. It was so surprising we reran this test an additional 4 times but got results which were basically the same so it seems that the Adaptive Memory Technology does not play nice with Crystal DiskMark.

PCMark Vantage

While there are numerous suites of tests that make up PCMark Vantage, only one is pertinent: the HDD Suite. The HDD Suite consists of 8 tests that try and replicate real world drive usage. Everything from how long a simulated virus scan takes to complete, to MS Vista startup time to game load time is tested in these 8 core tests; however we do not consider this anything other than just another suite of synthetic tests. For this reason, while each test is scored individually we have opted to include only the overall score. Unlike our other tests, the PCMark Vantage results are the average of five runs.

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The performance result the Momentus XT 500GB posted is certainly impressive for a hard drive - as it easily beats even a VelociRaptor – but once again they are not in the same league as what a Solid State Drive can do.

 

[AkG]

AS-SSD / Access Time

AS-SSD

AS-SSD is designed to quickly test the performance of your drives. Currently, the program allows to measure sequential and small 4K read/write speeds as well as 4K file speed at a queue depth of 6. While its primary goal is to accurately test Solid State Drives, it does equally well on all storage mediums it just takes longer to run each test as each test reads or writes 1GB of data.

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Once again we are seeing some slightly odd results; and once again we reran these tests an additional four times just to make sure. The Adaptive Memory Technology just doesn’t seem to like certain synthetic tests. We ran into this same issue when we tested the SilverStone HDDBoost so it is not exactly all that surprising.

Access Time

To obtain an accurate reading on the read and write latency of a given drive, AS-SSD was used for this benchmark. A low number means that the drive’ data can be accessed quickly while a high number means that more time is taken trying to access different parts of the drive.

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Since the other parts of AS-SSD did not particularly like the Seagate Momentus XT 500GB, it really is not all that surprising that it is merely posting decent results here.

 

[AkG]

ATTO Disk Benchmark

ATTO Disk Benchmark

The ATTO disk benchmark tests the drives read and write speeds using gradually larger size files. For these tests, the ATTO program was set to run from its smallest to largest value (.5KB to 8192KB) and the total length was set to 256MB. The test program then spits out an extrapolated performance figure in megabytes per second.

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Well it seems that there certainly is a lot of room for improvement with the “Adaptive” part of the Adaptive Memory Technology. Once again the numbers we got after even 12 runs of ATTO were good for a 7200RPM hard drive, but they weren’t earth shattering. It really does seem that synthetic test suites are for the most part not going to shed much light on the power of the XT series.

 

[AkG]

Real World Data Transfers

Real World Data Transfers

No matter how good a synthetic benchmark like IOMeter or PCMark is, it can not really tell you how your hard drive will perform in “real world” situations. All of us here at Hardware Canucks strive to give you the best, most complete picture of a review item’s true capabilities and to this end we will be running timed data transfers to give you a general idea of how its performance relates to real life use. To help replicate worse case scenarios we will transfer a 10.00GB contiguous RAR file and a folder containing 400 subfolders with a total 12,000 files varying in length from 200mb to 100kb (10.00 GB total).

Testing will include transfer to and transferring from the devices, using MS RichCopy and logging the performance of the drive. Here is what we found.

All in all, the results were quite good but once again this test couldn’t allow the Seagate XT’s technology to shine. The reason for this is simple: we were pushing and pulling 10GB of data and the NAND portion of the drive is only 4GB. This gives the Momentus XT 500GB a decent performance boost but not one that can really compete against the likes of a entry level SandForce solid state drive. More importantly this also underscores the main weakness of this unit: the fact that 4GB of NAND is simply not enough. Seagate really should have made it 8GB or 16GB as a paltry 4GB is simply too small for you to get good results across even a small portion of the 500GB data the Momentus XT can hold.