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

Hybrid Hard Drives: All About Compromise

Once you've used an SSD, it's hard to go back to a system armed with a hard drive. SSDs facilitate a more responsive computing experience, even if the peak performance capability of an SSD goes underutilized in a client environment.

For instance, those high I/O numbers we often see specified are almost impossible to realize on the desktop, particularly at the high queue depths needed in order to hit them. As a consequence, you can end up paying a premium for stated performance that'll never go to improving the way you use your PC. 

Conversely, we've seen that the poor performance of a hard drive can be masked by the file system cache. But the file system cache has to obtain and write data to the hard drive at some stage and, when this occurs, there's the potential for significant delays. This is most evident during the boot-up process, and when applications or games are first loaded.

The poor benchmark performance that you initially get from a hybrid hard drive like Seagate's Momentus XT would make it very easy to write off when, in reality, it can quickly adapt its performance to look a lot like an SSD in a great many scenarios. Due to the non-volatile nature of NAND, “hot” data is available as soon as the boot-up process starts, resulting in accelerated load times and a more responsive system that's available as soon as the desktop appears.

Really, the only time Seagate's Momentus XT slowed down drastically compared to an SSD was when we installed the operating system and applications. Once everything was fully loaded, however, performance rapidly improved as the drive's software algorithms pulled the most frequently-access data into flash, bestowing very SSD-like qualities to it. At that point, it was frankly hard to tell the difference during most common tasks.

Of course, the Momentus XT's greatest advantage is its large capacity and low cost per bit compared to the SSDs it so actively strives to behave like, which makes it a very tempting proposition for those who're able to tolerate occasional periods where the drive's performance necessarily dips back to what you'd see from a hard drive.

  • hmp_goose
    So the turntable was two or three gens old?
    Reply
  • 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.
    Reply
  • 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.
    Reply
  • manwell999
    The probability that your hard disk or ssd is going to fail is 1:1.
    Reply
  • hunshiki
    The idea is great in my opinion, but they could include a 16gb SSD inside the drive. Or 32.
    Reply
  • 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.
    Reply
  • 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?
    Reply
  • 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.
    Reply
  • 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).
    Reply
  • 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?
    Reply