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Why 2.5” Drives Are Getting More Important

Desktop Backplane? Three 2.5" HDD Solutions Reviewed
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The larger platter surface area of 3.5” hard drives makes them indispensable for reaching high capacities--currently up to 2 TB (check out Seagate’s 1.5 TB Barracuda 7200.11). Hence, these drives typically are the nearline backbones of data centers and file servers, and are the mainstay of small offices and home machines. However, the market for 3.5” hard drives isn’t growing as fast as the market for 2.5” drives, for various reasons.

#1 Mobile Computing

Mobile computing is the main growth factor for the 2.5” drive segment. All full-format notebooks and laptops rely on 2.5” hard drives, mostly utilizing Serial ATA. 500 GB notebook drives have been available for a while, although fully standardized models that are based on only two platters are significantly more recent. While the mainstream will still be at the 160 GB and 250 GB capacity points, we will see notebook drives reaching 750 GB in early 2009, moving the mainstream up to 320 GB. All of this is sufficient for notebook PCs, which are still seeing significant growth, as new users tend to get a notebook instead of a desktop PC, and even those who use desktops decide to get a notebook as a second system.

#2 Increased Storage Densities

Whenever high storage performance is required, a large number of state-of-the-art hard drives is imperative, as this is the only way of creating storage arrays capable of processing a maximum number of I/O operations per second. Flash-based solid state drives (flash SSDs) are many times faster than conventional drives, but these products may not always provide the capacity required for enterprise applications.

SATA vs. SAS (bottom): The SAS connectors are merged into one wide plug.SATA vs. SAS (bottom): The SAS connectors are merged into one wide plug.

To achieve high storage density and high I/O density, fast 10,000 RPM and 15,000 RPM drives based on the 2.5” form factor turned out to be the best choice, beating 3.5” drives when it comes to I/O performance, while lagging only slightly behind in throughput. In addition to their increased densities, a set of 2.5” drives typically provides more I/O performance than a comparable array consisting of 3.5” drives. As a result, overall power consumption is smaller as well.

#3 Convergence and Cost Pressure

2.5” mobile drives, as well as enterprise drives (2.5” and 3.5”), are often based on the same platter diameters, allowing drive manufacturers to use a certain number of shared components. The resulting products may still be completely different, but cost pressure is a huge issue these days if you look at average prices for 2.5” notebook hard drives. For example, 320 GB models start at less than $70, while 500 GB drives cost $110 and up. Compared to the money you had to spend on hard drives only a few years ago, that’s almost sensationally cheap, but 3.5” desktop drives still typically provide twice the capacity at the same price points.

#4 Mobile Storage Options

Notebooks will increasingly be using flash SSDs for the sake of increased system performance. But this also means that capacities will stay at the level they are today, which will have many users purchasing an additional storage drive. Obviously, 2.5” SATA drives are the perfect companions for travel if your notebook’s drive cannot provide sufficient capacity.

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  • 0 Hide
    gpsxsirus , April 9, 2009 8:45 AM
    I'd like to see a review of some backkplanes that support a couple more drives that's still mountable in an ATX case. I'm looking to run RAID 5 or 6, ideally with a hot spare.
  • 1 Hide
    BKD , April 9, 2009 12:12 PM
    How about 2x5.25" bays hosting vertical 3.5" disks, maybe five or six? I prefer this setup to the standard desktop internal cages which are a pain.

    gp-Just use more then one of the above-the raid is controller dependent.
  • 1 Hide
    WyomingKnott , April 9, 2009 1:49 PM
    BKDHow about 2x5.25" bays hosting vertical 3.5" disks, maybe five or six? I prefer this setup to the standard desktop internal cages which are a pain.

    And here it is: http://www.addonics.com/products/raid_system/ae4rcs35nsa.asp
  • 1 Hide
    joex444 , April 9, 2009 3:49 PM
    Almost, its a 3x5.25" but you need that with 3.5" drives. 2x5.25" can only get you 3 horizontal 3.5" drives.
  • -4 Hide
    yourhighness , April 9, 2009 5:02 PM
    I saw this article and I though, Awesome this is going to be a great article that will apply to me (and enthusiast and a Small Business).

    But then I noticed it's all about 2.5" hard drives instead of 3.5"...

    FAIL
  • -1 Hide
    yourhighness , April 9, 2009 7:25 PM
    yourhighnessI saw this article and I though, Awesome this is going to be a great article that will apply to me (and enthusiast and a Small Business).But then I noticed it's all about 2.5" hard drives instead of 3.5"...FAIL

    Sorry to be debbie downer, I just feel that the vast majority of people looking to add storage space would prefer the larger, cheaper, faster 3.5" form factor of the 2.5" drives.

    I understand that SSD is changing things, but it still costs 10-100X more than 3.5"HDD, and 2.5"HDD still costs 2-5x as much as 3.5"...

    I guess it would be more productive to ask for 3.5" backplanes than just being a dick.

    Please can I see some 3.5" storage solutions? I'd especially like to see some of the drive bays supporting more than 4 drives.
  • 1 Hide
    Anonymous , April 9, 2009 8:57 PM
    http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=backplane&x=0&y=0

    for a list of backplanes out there
  • 0 Hide
    Anonymous , April 9, 2009 10:00 PM
    Having 40mm fans very close to rotating media is a very bad idea. Hard drives do not like the intense vibration from high speed fans.
    Performance and reliability suffer badly. I would like to see the issue
    addressed in a serious way, not just the obvious user oriented features.


  • 0 Hide
    michaelahess , April 10, 2009 4:10 AM
    Tom StephensonHaving 40mm fans very close to rotating media is a very bad idea. Hard drives do not like the intense vibration from high speed fans.Performance and reliability suffer badly. I would like to see the issue addressed in a serious way, not just the obvious user oriented features.


    Except when using, oh I don't know, laptop drives that are already built to withstand this kind of abuse, kind of a non-issue.

    Also considering how hot many laptop drives get when on your lap, I don't think heat will be as big of an issue as you'd think if your case is cooled properly. My Stacker 830 would be a perfect fit if I threw one of these in my top bay, just fashon a air guide for the top fan to pull air from the first bay, turn the 40mm fans off and be happy!
  • 1 Hide
    Anonymous , April 10, 2009 3:21 PM
    Bought This - Returned it the next week: No stress relief on the connections and several came disconnected due to the fact that the SAS/SATA connections were only held on to the circuit board via the soldier holding the pins in place - Hey! I paid $40 for this backplane that was little more than 4 places to mount hard drives, what do you expect?
  • 1 Hide
    kenyee , April 13, 2009 2:03 PM
    I'd like to see a similar roundup but with 3.5" HDD backplanes. There are quite a few that fit into three 5-1/4" slots and is a better compromise if you run a mid-tower...
  • 0 Hide
    Anonymous , April 13, 2009 10:17 PM
    Excellent review, however it seems like the backplanes that you choose to review all are approximately the same unit with a different brand pasted on... would like to see some more diversity in the choices.
  • 0 Hide
    ShadowFlash , April 13, 2009 11:21 PM
    Any word yet on the patriot, OCZ, or A-DATA versions of the mobile backplane ? I think any of those would work alot nicer in the desktop enviornment, as they fit neatly into a single 3.5" bay. There are also a number of chinese 2-bay RAID enclosures out there, but who knows the quality? I would really like to see a true round-up on those.

    For those who don't see the point in 2.5" vs. 3.5", consider a ultra-fast OS/Program array, and a nice fast RAID 10 array for storage, and pretty soon you're running out of physical space in the average desktop case, not to mention competing for power with your high-end video card. While 2.5" drives are still a bit pricey for storage drives, a pair of 73GB 15K SAS and a dual RAID 0 enclosure for about $300 is certainly worth it ( or even 4x 36GB 15K for the same price ), as space requirements are simply not needed for an OS/program drive.
  • 0 Hide
    mikolay , April 15, 2009 3:08 PM
    SuperMicro Backplane CSE-M28E2B for 8x 2.5"HD, 2x 5.25"Bay; Redundant 2x4xSAS port :) 

    http://www.span.com/catalog/product_info.php?products_id=15973&language=en
  • 0 Hide
    mileage , April 16, 2009 5:05 AM
    is there any internal enclosure fit two of 2.5" hdd into one of 3.5" bay?
  • 0 Hide
    ShadowFlash , April 16, 2009 5:00 PM
    mileageis there any internal enclosure fit two of 2.5" hdd into one of 3.5" bay?



    Here's the RAID version from A-DATA....they also have non-raid versions I believe.

    http://oc.adata.com.tw/1_product_detail.asp?pid=ASX1SUMAL-2

    I have not found any reliable review on these type of things yet. There are a number of chinese versions off of E-bay which look to be identical and both Patriot and OCZ are promising their vervisions as well. I doubt these would get rid of the stuttering problems of low-end SSD's, but it would make for some nasty RAID-on-RAID action, spawning all sorts of bizarre set-ups.
  • 0 Hide
    mileage , April 16, 2009 8:20 PM
    Thanks for the info.
    I found one for internal for two of 2.5inch to one bay of 3.5 inch.

    http://www.acmemicro.com/estore/merchant.ihtml?pid=6982&lastcatid=390&step=4

    I'll test this later today for our product test.