It's been over a year since I reviewed Seagate's first hybrid hard drive: the 500GB Momentus XT. At the time I felt that it wasn't nearly as good as an SSD, but likely the best 2.5" hard drive money could buy. Armed with only 4GB of SLC NAND acting as a read cache, the original Momentus XT delivered VelociRaptor performance in a much more power efficient package. 

Since then Seagate hasn't updated or expanded its line of hybrid HDDs at all. I kept hearing rumors of new drives coming but nothing ever surfaced. More recently Seagate announced that the next version of the Barracuda XT will be a hybrid drive as well.

Today Seagate is announcing availability of its second generation Momentus XT. Now at 750GB with 8GB of SLC NAND (once again, as a read cache), the new Momentus XT is a definite evolution over its predecessor. With a larger NAND cache Seagate can be more aggressive with its caching, not to mention the improvements to the mechanical side of the drive as well. The entire package is still not nearly as fast a value SSD, but it's doing much better than mechanical (3.5" included) hard drives in our tests.

Write caching is still not enabled on the NAND, however Seagate is planning on enabling it via a firmware update sometime in 2012. I've seen results from an early version of the write caching firmware and the improvement is tangible. 

The 750GB Momentus XT will be available at a MSRP of $245.

We're still hard at work on our review of the drive, expect to see it later this week!

Update: Our review is live!

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  • etamin - Wednesday, November 30, 2011 - link

    Technically OCZ has a hybrid drive, but it is PCIe and beyond the commoner's wallet.
  • mikemayousa - Tuesday, November 29, 2011 - link

    With the prices of SSD's falling so quickly, it just makes no sense to sell me a 250 dollar hybrid drive when I can buy a small SSD and a mechanical drive(external for laptops) for the same price and get insanely better performance.
  • jb510 - Tuesday, November 29, 2011 - link

    YMMV, but in testing of the 500GB XT drive Anand showed it was reasonably close to SSD performance for real world light desktop loads and while i've never worked daily on an SSD equiped computer, my personal experience having briefly gone back and forth is that my 500GB XT is way way way faster than 500gb 7200rpm and 750gb 5400rpm drives.

    Personally I've tried many configurations over the years and never been happy with external solutions to my storage needs, they are both physically cumbersome and SLOW (even the fw800 drives I use).

    My 500gb Momentus XT has served me well for a year moving from my 2008 MBP to a 2011 MBP. I've been considering a 512gb SSD now that they are under $1k to replace it. Smaller than 500gb would just never work for me, as I already offload files (photos/media) to a network every couple months which is inconvenient. This new 750gb drive at $250 though is very attractive to get me and comfortably get me through another year as SSD prices continue to drop.
  • tester1 - Tuesday, November 29, 2011 - link

    Just wondering if anyone has tested the new 750GB XT vs the old 500GB XT to see if they notice any performance difference.

    Also I am wondering if anyone has tested the performance while running Full Disk Encryption software like BitLocker etc.
  • kyuu - Tuesday, November 29, 2011 - link

    With twice the NAND, improvements to the firmware, and the inclusion of write caching in a firmware update in the next couple months, these should be significantly faster than the 500GB Momentus XTs.
  • kyuu - Tuesday, November 29, 2011 - link

    I hope to see Anand doing a review on these soon!
  • phoible_123 - Tuesday, November 29, 2011 - link

    I was super-excited about the hybrid drive when it came out, but that was because SSDs were $2-3 per Gigabyte, so a 256GB SSD would literally double the price of your laptop (or increase it by 50% if you run a Macbook Pro). I had a hybrid drive in my last work laptop, and it was definitely faster, although nothing compared to an SSD.

    Over the following year, the prices of SSDs dropped enough that cost became much less of a factor. I bought a 240GB SSD for around $300 when I got my new MBP this summer. You can now get a 240GB drive for about $240 if you get a good deal. Sure, it won't be SATA3, but you can get an Agility 3 for as little as $300 if you get a great deal. The prices of SSDs are dropping to the point where they will soon obsolete HDDs.

    Most people just don't need 750GB of capacity. I kept buying 500GB drives, and found that I never filled up more than 200GB. I even bought the sled that would let me take out my optical drive and replace it with the original drive from my system (or another SSD). I never bothered. I bet that, within the next year we will see 480GB SSDs for reasonable prices.

    The big downside of these hybrid drives are that they are complicated. If either drive fails, you are SOL (kind of like running a RAID setup). The original Momentus XT got lots of complaints on Newegg (of the 3 we had at work, 1 failed). I suppose that when they can enable write caching and up the SSD size significantly, you will see performance equivalent to an SSD. OCZ's Revodrive hybrid is pretty much the same speed as an SSD (faster even because it has 2 controllers for double the channels), but it has a 100GB SSD cache drive, and it would likely be impossible to put 1TB + 100GB in a 2.5in case.

    Overall, for enterprise customers who need lots of storage space, the hybrid approach could make sense, but for the rest of us, it was an interim solution that has seen its time.
  • anactoraaron - Tuesday, November 29, 2011 - link

    Since really these drives are just "enhanced" and not true hybrids. I think to earn the "hybrid" terminology performance would be 50-75% of your traditional SSD in EVERY performance benchmark. These drives don't quite do that and the 1st gen wasn't even close. I am looking forward to the review, however, I doubt there will be more than a 5-10% improvement over the 1st gen. Even with 8gb nand you will still be using the platter portion way too often and performance will not be close to being as good as a SSD.

    Are they better than your traditional 5400or7200 RPM drive? Yes. But not by that much and you have a small premium to pay for it (not counting the current HDD prices).
  • alcalde - Tuesday, November 29, 2011 - link

    8 GB would be almost enough to cache my entire OS and every program installed along with logs, temp files, etc.. Why would you be "using the platter portion way too often"?

    Your performance WILL be as good as an SSD on those items that are cached in the NAND. Just as studies have shown that most users with numerous apps installed on their smart phones only use five or six regularly, the same is no doubt true of most users' laptops (and a lot of the OS is probably composed of libraries that rarely or never get used).
  • Hubb1e - Tuesday, November 29, 2011 - link

    These drives only cache small files that are randomly accessed as that is the traditional weak spot on a mechanical drive. They may never be as fast as an SSD, but the benefits of a mechanical drive without the big random access drawback are where it counts. As long as the read cache is big enough for these small files, your machine will perform faster and more consistent. Sequential performance on a mechanical drive is still within an order of magnitude of an SSD so that's not the weak link.

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