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Never The Twain Shall Meet

Portable Performance: Four USB 3.0 Enclosures For Your 2.5” Drive
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The remarkable words of Rudyard Kipling that describe the gulf between eastern and western philosophies might just as easily be used to describe USB 2.0 and USB 3.0 signaling. We hear a lot of references to “backwards compatibility” bandied about in the discussion of USB connectors, but unlike USB 1.1 and 2.0, there’s a lot more behind the change to USB 3.0 than a simple signaling rate. Indeed, the term “backwards compatibility” doesn’t really describe how these interfaces coexist as separate technologies.

Type B cable ends, including Micro USB, USB, and their USB 3.0 derivativesType B cable ends, including Micro USB, USB, and their USB 3.0 derivatives

The easiest-to-describe difference is SuperSpeed USB’s use of 8b/10b encoding, which is only part of what makes the signals incompatible. It’s because of this signal incompatibility that USB 3.0 connectors have an extra five signal pins, which allow USB 3.0 and USB 2.0 to coexist. Coexistence also allows bus-powered USB 3.0 devices to take their power from the previous version’s power pins and the USB 3.0 specification even increases the current limit of the previous-generation connector from 500mA to 900mA.

Differences don’t end at the connector, as SuperSpeed USB also requires its own controller interface. Companies have fortunately figured out how to put multiple interfaces on a single device, such as the ASMedia bridge above. Used in all four of today’s comparison enclosures, the ASM1051 hosts SATA over USB 3.0 and USB 2.0.

The presence of a USB 2.0 controller on USB 3.0 devices means that devices can be used with the smaller USB 2.0 cable, while reverting to USB 2.0 speeds. This could come in handy during an emergency, since replacement USB 2.0 cables are far easier to find.

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  • 0 Hide
    Anonymous , April 14, 2010 8:39 AM
    I know this isn't relevant, but what is in the pcie1 slot?
  • 3 Hide
    Gin Fushicho , April 14, 2010 8:41 AM
    You guys are really benching cases? I figured they'd all be close to the same anyway.
  • 5 Hide
    Crashman , April 14, 2010 9:10 AM
    SubSonix1I know this isn't relevant, but what is in the pcie1 slot?


    Nothing, the slot is covered by an extended chipset heat sink.
  • -4 Hide
    TomD_1 , April 14, 2010 10:50 AM
    So basically, they all have identical hardware, and IMO all look ugly
  • 1 Hide
    Crashman , April 14, 2010 10:59 AM
    TomD_1So basically, they all have identical hardware, and IMO all look ugly


    You forgot to mention they all fit in a shirt pocket. That is the most important part.
  • 7 Hide
    warmon6 , April 14, 2010 12:42 PM
    thejerkScraping the bottom of the barrel for non-iPad news?


    Um.... few things,

    1. They haven't been just covering the ipad. They been covering alot of other things.

    2. This isn't news. This is a review. Learn the difference.
  • 1 Hide
    kelfen , April 14, 2010 12:45 PM
    if ya think about it this is more cost effective per GB to buy one of these and a hard drive then buying a usb drive
  • -7 Hide
    Anonymous , April 14, 2010 12:59 PM
    Good... so I can share my pirated movies more faster?( sarcasm )
  • -1 Hide
    rooket , April 14, 2010 4:07 PM
    What's the performance like if you use it with a hard drive? Just same as usb 2.0 I'd imagine? Odd that they're only hitting 35MB/sec with USB 2.0. It should go 60MB/sec. Why is this only half the speed?
  • -1 Hide
    shin0bi272 , April 14, 2010 4:14 PM
    Hey great review... will be nice when I actually get a usb3 mobo or card... transferring 1.03TB of data over usb2.0 is just a total PAIN in the backside. I should have just opened the case and plugged the drive directly into the pc I know but I didnt and I had to wait about a DAY because of my laziness. Now with usb3 that wont be an issue and its good to see that at least someone is benchmarking external enclosures. Granted I do have to agree with the sentiment that you guys must be bored or out of stuff to review if youre reviewing external enclosures lol. But thanks all the same.
  • 2 Hide
    Snipergod87 , April 14, 2010 4:45 PM
    rooketWhat's the performance like if you use it with a hard drive? Just same as usb 2.0 I'd imagine? Odd that they're only hitting 35MB/sec with USB 2.0. It should go 60MB/sec. Why is this only half the speed?


    USB 2.0 always tops out at 30-35MB/s because of the overhead. Thomas was wrong in saying they can reach 60MB/s.
  • -1 Hide
    delazaren , April 14, 2010 4:49 PM
    why the hell design a plug that consists of two parts???? No way an engineer designed this, it must have been a committee of some sort.
  • -1 Hide
    mark0718 , April 14, 2010 4:52 PM
    How do the they know that the external boxes and not the motherboard side is the limiting factor?

    Actually, is one side or the other by itself the limit. Perhaps there
    is a transaction overhead that is the some of both sides' response time,
    rather than a turn-around time that would be limited by the slower side.
  • -1 Hide
    cadder , April 14, 2010 4:55 PM
    Quote:
    why the hell design a plug that consists of two parts????


    To maintain compatibility with USB 2.0 cables and plugs. Buy one of these enclosures, plug in a standard USB 2.0 cable, and connect it to your laptop. Plug in the 3.0 cable and connect it to your desktop.
  • -1 Hide
    cadder , April 14, 2010 4:58 PM
    Quote:
    Nothing, the slot is covered by an extended chipset heat sink.


    Ah, better views of it are here:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16813128413&Tpk=X58A-UD7
  • -1 Hide
    warmon6 , April 14, 2010 8:33 PM
    Quote:
    USB 2.0 always tops out at 30-35MB/s because of the overhead. Thomas was wrong in saying they can reach 60MB/s.


    Yep, So true. If there wasn't as large of a overhead, maybe HDD, SSD, Flash drives could run at a moderately comfortable 45-50MB/s on usb 2.0.
  • -1 Hide
    thejerk , April 14, 2010 9:46 PM
    warmon6Um.... few things,1. They haven't been just covering the ipad. They been covering alot of other things.2. This isn't news. This is a review. Learn the difference.


    I have a review of your mom: She's awesome.
  • -1 Hide
    Anonymous , April 14, 2010 11:06 PM
    "We have no idea why a clear plastic sheet runs through the Kingwin ATK-25U3-BK interior"

    Keeps drive PCB from possibly touching the metal enclosure and shorting out. There are some scenarios which could lead to this: the bottom of the enclosure being pushed in or the drive not having bottom screw holes.
  • -1 Hide
    FrozenGpu , April 15, 2010 1:32 AM
    thejerkI have a review of your mom: She's awesome.


    LOL! you too?
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