In The Lab With Seagate's Momentus XT 750 GB Hybrid HDD

Benchmark Results: Boot-Up In hIOmon

Based on the preceding page's ASU benchmarks, Seagate's Momentus XT looks a lot more promising. But let’s first consider how synthetics translate to the real-world before getting too ahead of ourselves.

For this, we're using hIOmon, a file and disk I/O performance measuring tool that can concurrently monitor I/O operation activity within three distinct levels of the software and hardware stack: namely, the logical disk level (the file system), the physical volume level, and the physical device level. The image below helps visualize each level of the stack, and it comes from a SNIA webcast that discusses the complexities of how I/Os traverse the stack. You can find that webcast here.

Monitoring results from the logical disk level are obtained between the operating system I/O manager and the file system. Results from the physical volume level are gleaned between the file system and the volume manager, and results from the physical device come from in between the volume manager and the disk class driver.

The difference in I/O activity between the logical disk level and the physical disk can vary significantly. In the graphs below, we capture data from the latter portion of the boot-up process. Booting up consists of a number of stages, starting with a power-on self-test, proceeding on to the BIOS ROM and boot loader phase, and then the firing-up of various configured services and other start-up tasks.

hIOmon is normally configured to begin monitoring once the services start to load (hIOmon can optionally be configured to begin monitoring earlier in the process). Due to the dynamic nature of the boot process, the measurements taken can vary significantly from run to run, which is evident from our results below. The largest variation occurs at the logical disk level.

Although the difference in the amount of data transferred is quite significant, it does not (in this case) have a significant impact on the percentage of fast IOPS or the average block transfer size. To clarify, a fast I/O is an operation observed by hIOmon to have completed in less than one millisecond.

The boot-up processes that we monitored typically consist of approximately 88% random read access and 12% sequential read access, with an average queue depth of 1.4.

If there's one key take-away, it's that a significant amount of I/O activity can occur independent of the storage device, which significantly reduces demands made on the storage system. As a result, the potentially poor performance of a storage solution can be masked to a degree. This is evident in the increased percentage of fast IOPS and the higher maximum transfer rate achieved at the logical disk level when we monitor Western Digital's Raptor X.

When we monitor the Momentus XT's boot-up process, we see that performance increases at both the logical disk and physical device level for both the percentage of fast IOPS and the maximum transfer rate.

On Samsung's 830, the percentage of fast IOPS is identical at both the logical disk and physical device levels. Meanwhile, the maximum transfer rate increases at each level.

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  • hmp_goose
    So the turntable was two or three gens old?
  • sunsmasher
    So it sounds like the hot setup is SSD for OS/Apps, and HHDD for storage of frequently used media, with a 2TB+ hard drive for storage/archiving of other media.
  • americanbrian
    I don't like your spider graph for reliability.... Does the Hybrid Drive still "work" when either the flash or spinning discs fail?

    If not (which it is easy to argue it would at least not be working properly if at all). Then you must say it has twice the chance at failure. This is because if there is a 1:1000 chance of the HD part failing, and a 1:1000 cahnce of the flash failing (your spider shows them to be roughly equal) then there is a 2:1000 chance of "drive" failure in total (or 1:500).

    That is called "probability" it is funny like that. Think of it like a weird RAID 0 array.
  • manwell999
    The probability that your hard disk or ssd is going to fail is 1:1.
  • hunshiki
    The idea is great in my opinion, but they could include a 16gb SSD inside the drive. Or 32.
  • akamrcrack
    Would have been nice to see you include SSD caching drives like the Crucial Adrenaline in this study.

    My Adrenaline + Samsung Spinpoint F3 1TB 7200rpm HDD say they are the better buys :)

    Installed my OS onto my HDD (was originally on a Crucial M4 64GB) then installed the Caching software from Dataplex and watched the sparks fly!

    Now my Spinpoint runs as fast as my Intel 320 series 120GB SSD in CrystalDiskMark :)

    Plus I can always upgrade to a 2TB HDD meaning I can have 2TB of space running at SSD speeds all day :)

    When you are a srs gamer like me and you have hundreds of games to store and no SSD capable of holding them, you begin to want to find solutions to solve that. Well ever since I installed the caching drive + software (very simple) everything about my HDD is fast!

    Momentus is old and tried. The only thing I know of that can match the performance of my HDD+SSD cache is a new gen velociraptor 1TB HDD that costs around $320. Which could get me 2TB of storage and the SSD cache and still have money left over lol so neither new gen raptors or momentus are worth the cost unless you are limited to 1x 3.5" bay in your computer.. Even then a 2.5" SSD is very easy to hide in a case..

    I've seen the argument "why not just get a regular SSD instead of the Adrenaline, won't they do the same thing?"

    My response to that is, for the average user that wants simplicity getting a SSD premade for caching that comes with quality software is the way to go. The Dataplex software is very very light and as simple as install then forget it existed.
  • A comparison with Intel's SRT technology (combines up to 64GB SSD with a traditional HD) would have been interesting. I wonder what evidence made Intel choose 64GB and Seagate choose 8GB? What is the optimal amount of SSD to pair with an HD generally speaking?
  • mariusmotea
    To test a Hybrid drive you need to use it several hours. of course that benchmarks files has been cached into the SSD. Let's see the startul speed after i browse the internet for few hours and play a game for 30 minutes. I don't belive that the statup files will be in ssd anymore.
  • dthx
    Of course a SSD + big 3.5 drive is always a better solution but... impossible to achieve in most portable PC's. This is where the hybrid shines: you don't have to choose between decent performances and sufficient and affordable capacity. I've put such a drive (and Win7 instead of Vista) in a 4 year old XPS-1330 and after a few reboots it has become an extremely capable machine (faster than any brand new laptop with a conventional HDD).
  • cscott_it
    I recall another site (maybe Anandtech?) putting a couple of these in a RAID 0 configuration and the performance scaled rather nicely. Any chance you guys are thinking about doing something like that?
  • SinisterSalad
    I've had a few of the 500GB versions. Nice to see the improved capacities. The 4GB SSD on mine was enough until BF3 with their large maps came about. I've since gone to SSD on my primary machine, but I still like and recommend these drives.
  • cknobman
    I have issues with the fact that you benchmark the $150 Momentus against a sub $100 64GB SSD. It is very well known that 64GB SSD drives perform noticeably slower than larger SSD due to fewer channels. This review should have included at least 120GB SSD especially since they can be purchased for <$110.

    Also it is noted how well the Momentus performs after several runs of a game loading or booting the OS as it recognizes the pattern and keeps the data on a SSD. I would like to see if there is a huge performance impact of something like: 3 boots to get the OS on the cache, then 3 loads of a game, then reboot the computer. Does the reboot after the multiple run of the game load to put it on the cache take forever because there was not enough cache to accommodate all the OS and the game?
  • willard
    americanbrianThat is called "probability" it is funny like that.

    You might want to take a statistics class, because that's not how probability works.
  • willard
    manwell999The probability that your hard disk or ssd is going to fail is 1:1.

    Indeed. It's pretty useless to talk about failure rates without giving a time frame. Over a long enough time, everything must eventually fail.

    Entropy must increase.
  • Sakkura
    When it comes to comparing AS SSD benchmark results, the Momentus XT and Raptor X are an order of magnitude slower than Samsung’s 830, based on access time and 4 KiB performance results.

    Looks more like roughly TWO orders of magnitude, since performance seems to range from ~20x to ~200x.
  • willard
    akamrcrackNow my Spinpoint runs as fast as my Intel 320 series 120GB SSD in CrystalDiskMark Plus I can always upgrade to a 2TB HDD meaning I can have 2TB of space running at SSD speeds all day

    No you can't. You will never have 2TB of storage running at the speed of an SSD. Your SSD can only cache as much as the SSD can hold, and you don't get the full performance of an SSD with a cache drive anyway.

    Caches perform very well when there is a small amount of data that needs to be cached, but your example of "hundreds of games" is well beyond the capabilities of a cache drive.
  • willard
    SakkuraLooks more like roughly TWO orders of magnitude, since performance seems to range from ~20x to ~200x.

    20x to 200x is one order of magnitude. Two orders would be 20x to 2,000x.
  • Sakkura
    willardYou might want to take a statistics class, because that's not how probability works.

    When you're dealing with an either/or scenario, probabilities are actually additive; P (drive 1 or 2 failing) + P (drive 1 and 2 failing) = P (drive 1 failing) + P (drive 2 failing). Having two (or more) components that can each fail makes an overall failure more likely, assuming each component is just as error-prone as otherwise. The same thing affects RAID arrays, where adding drives increases the risk of a failure, unless compensated for with redundancy (redundancy can, however, increase reliability beyond that of a single drive too). A hybrid SSD/HDD drive is similar to a RAID0 array with 2 drives in regard to failure rates; if either drive fails, you're in trouble.
  • chesteracorgi
    Mr. Hart, a fairer comparison against the Momentus would be one of the caching drives from Corsair (Accellerator) or OCZ (Synapse) using Dataplex software, combined with a HDD. Now, it may not be exactly fair even then because the caching drives have more capacity than the Momentus: but the comparison is closer or apples to apples rather than apples to oranges. But bot the technology involved and cost make thie caching SSD/HDD combination relatively even.
  • Sakkura
    willard20x to 200x is one order of magnitude. Two orders would be 20x to 2,000x.

    What I meant was that the SSD outperforms the other drives by factors of around 20 to 200 on the indicated parameters. That's about 1.3 to 2.3 orders of magnitude.
  • Tedders
    So basically, it literally is a blend of both worlds good and bad. But the more you use this HHDD the better it performs as it learns over time what you use the most? SO right now, if it were in my rig it would load Max Payne 3 really really fast as I have playing the crap out of it. Am I correct?
  • willard
    SakkuraWhen you're dealing with an either/or scenario, probabilities are actually additive

    No they aren't, you can only add probabilities when they are mutually exclusive. For example, the chance of getting Heads or Tails when flipping a coin is 100% (50% + 50%). However, the chance of getting a Heads after two flips is not 100%, because you can't add the probabilities.

    Similarly, the probability of failure of something is not the sum of the probability of failure of each of its components. Consider a hypothetical piece of equipment with five components, each of which has a 20% failure rate over a period of one week.

    After one week, there is not a 100% chance that the equipment has failed. It is very likely that it has, but the probability is not 100%, or even very close to that. There is about a 33% chance that the equipment is still functioning after that week. If we're considering failures to be random events (as the average HDD failure is), there is still a 33% chance that the equipment still works after another week, given that it survived the first week.
  • willard
    SakkuraWhat I meant was that the SSD outperforms the other drives by factors of around 20 to 200 on the indicated parameters. That's about 1.3 to 2.3 orders of magnitude.

    Ahh, I stand corrected then.
  • Farrwalker
    With the relatively low price of 4GB 240-Pin SDRAM DDR3 1600 four sticks can be had for under $100. With a system that has 16GB of RAM, is it possible for software to accomplice what a hybrid hard drive does?

    Assuming that a system has 16GB of RAM and a 1TB hard drive, is there software to use the RAM in the motherboard as a hybrid uses the flash memory contained with in the hybrid drive to increase read and writes?