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Getting Good Speed From USB 3.0

Does The USB 3.0 Controller On Your Motherboard Matter?
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USB 2.0 (Red) & USB 3.0 (Blue)USB 2.0 (Red) & USB 3.0 (Blue)

Nearly every motherboard sold today comes with USB 3.0 support (the blue ports in the image above). And, based on our results, we're happy to say that you really don't have to worry about the USB 3.0 controller your board vendor of choice uses on its platforms. Frankly, the devices you plug into a USB 3.0 controller are going to limit performance, not the controller itself. There isn't an individual device we've seen able to push the upper limits of what this standard accommodates; you'd need to push more than 500 MB/s to saturate a PCIe x1 link and the intermediary controller. And even with two of Kingston's fast external SSDs attached to one controller, we still didn't tag that limit. 

It doesn't take an engineer to figure out why this is the case, though. Currently, all of the fastest USB 3.0-based external drives employ SATA 3Gb/s SSDs, limiting their peak performance to about half of what the bus can handle. Stepping up to a pair of 6 Gb/s devices hammering USB 3.0 would likely cause more of a jam-up. However, the extra cost for even faster external devices probably wouldn't attract a ton of attention, since they'd be faster than most folks' internal storage subsystems. Perhaps someday soon we'll see SF-2200-based USB 3.0 drives able to push the standard's limits. For now, though, that's pretty unrealistic, meaning that you aren't going to see a difference between USB 3.0 controllers.

The key differentiator between USB 3.0 controllers will come with Windows 8. Microsoft plans to provide native driver support for USB-attached SCSI (UAS), anticipated to support NCQ instructions over USB. As a result, you can expect to benefit from an SSD's ability to reorder operations to take advantage of multi-channel architectures, which generally result in higher performance as queue depth increases.

A simple operating system upgrade won't enable NCQ over USB. In addition to the software driver, proper functionality will require a compatible USB 3.0 controller and client device on the other end. ASMedia's ASM1042 already contains logic that should support UAS, but we don't know the status of AMD's A75 or Etron's EJ168. Things are even less clear at the device-level because we don't know if any of the external peripherals out right now are UAS-ready.

That's future stuff, though. Until we get there, you can go on enjoying the blazing-fast speed of USB 3.0 knowing that, for the most part, it's really hard to saturate the throughput of a single port, and even two ports originating from the same controller deliver reasonable performance. If you're lucky enough to own four of Kingston's fast HyperX Max 3.0 drives and want to plug them into AMD's A75 chipset or HighPoint's RocketU 1144A, you should see comparably-good speed, too.

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  • 4 Hide
    nikorr , October 20, 2011 4:49 AM
    Great article!
  • 3 Hide
    amk-aka-Phantom , October 20, 2011 5:17 AM
    Asus changed the USB 3.0 controller on their P8P67 line of boards... I think they switched to ASMedia from NEC, and I'd love to see the difference between the two benchmarked. I think this article has way too few controllers; there're more USB 3.0 solutions on the market.

    Well, at least the article showed that it's possible to reach 150 MBps write speeds and higher... good enough for me. Now all I need is a USB 3.0 drive :) 
  • 6 Hide
    The Greater Good , October 20, 2011 6:07 AM
    That's why eSATA is the best for external storage. USB is great for everything other than data throughput.
  • 0 Hide
    de5_Roy , October 20, 2011 6:58 AM
    thanks for the article! i always use usb drives, most of the old drives using usb converters. good to know i can run multiple of them without hitting speed limit.
  • 0 Hide
    lockhrt999 , October 20, 2011 8:06 AM
    They should have included windows 8 in this benchmark. On my system win7 writes at 3-4 MB/s to thumb drive and win8 writes at constant 10 MB/s to same thumb drive. (Everything's USB 2.0 though). Some witchcraft :D  I don't know but they should have included win 8.
  • 3 Hide
    lp231 , October 20, 2011 3:37 PM
    The Greater GoodThat's why eSATA is the best for external storage. USB is great for everything other than data throughput.


    I've tried eSATA and found out it's not as user friendly as USB.
    You will need a external power source if the eSATA isn't self powered.
    Then you will also have to setup the right bios config or the eSATA won't
    work properly like it's suppose to and basically the eSATA drive becomes a internal cause you lose the ability of hot plugging and swapping.
  • 2 Hide
    lockhrt999 , October 20, 2011 5:49 PM
    lp231I've tried eSATA and found out it's not as user friendly as USB. You will need a external power source if the eSATA isn't self powered.Then you will also have to setup the right bios config or the eSATA won'twork properly like it's suppose to and basically the eSATA drive becomes a internal cause you lose the ability of hot plugging and swapping.


    What? Even internal drives can be hot plugged and swapped. OS recognizes both internal and external sata drives alike. Once you connect it just go into My computer > manage > devices and search for new drives. To unplug simply right click on that drive and click disable. Even this can be done with IDE (ATA) provided you don't use old P4 era motherboards.
  • 4 Hide
    Crashman , October 20, 2011 6:03 PM
    lockhrt999What? Even internal drives can be hot plugged and swapped. OS recognizes both internal and external sata drives alike. Once you connect it just go into My computer > manage > devices and search for new drives. To unplug simply right click on that drive and click disable. Even this can be done with IDE (ATA) provided you don't use old P4 era motherboards.
    You started off right but then went soooo wrong.
    1.) Motherboards with hot-plug capability to internal drives were available almost from the beginning. Nvidia was famous for adding this function to its drive controller firmware, and ASRock was famous for adding it to the drive controller firmware of boards with other chipsets.

    2.) To this very day, the ports of many NEW motherboards STILL lack firmware support for this function on at least some of the ports. A few lack hot swap firmware on all of the ports, and a many have this feature selectable in BIOS.

    So, even though you're part right, the person you responded to is more right.
  • 3 Hide
    lockhrt999 , October 20, 2011 7:15 PM
    CrashmanYou started off right but then went soooo wrong.1.) Motherboards with hot-plug capability to internal drives were available almost from the beginning. Nvidia was famous for adding this function to its drive controller firmware, and ASRock was famous for adding it to the drive controller firmware of boards with other chipsets.2.) To this very day, the ports of many NEW motherboards STILL lack firmware support for this function on at least some of the ports. A few lack hot swap firmware on all of the ports, and a many have this feature selectable in BIOS.So, even though you're part right, the person you responded to is more right.


    Thanks for filling me. Coincidentally I never came across motherboard that doesn't support hot plugging out of the box that's why I thought everyone supports it.
  • 0 Hide
    Anonymous , October 20, 2011 7:37 PM
    I am a little surprised to see no mention made of USB 3 connections being dropped when plugging a (supposedly) USB 3-capable external dock or enclosure into a motherboard port connected to a Renesas/NEC USB 3 controller. Speculation faults, for instance, the JMicron USB 3 controller on the dock/enclosure; ASMedia is speculated to be less problematic. At any rate, "real world" experience finds dropped connection problems, which makes speed a secondary concern. Can this "dropped USB 3 connection" issue be addressed as well? Thanks.
  • 1 Hide
    ZakTheEvil , October 20, 2011 8:21 PM
    USB3 on my Gigabyte board was very unstable, hard drives would frequently disconnect. Disabling USB3 Power Management helped somehow, but they still often didn't appear after boot. I tried all available driver versions to no avail. I'm running Windows 7x64, by the way. Also, the enclosures I tried wouldn't spin the drives down after the host PC was shut down. I finally got two eSATA enclosures instead.
  • 1 Hide
    ZakTheEvil , October 20, 2011 11:11 PM
    dbguyI am a little surprised to see no mention made of USB 3 connections being dropped when plugging a (supposedly) USB 3-capable external dock or enclosure into a motherboard port connected to a Renesas/NEC USB 3 controller. Speculation faults, for instance, the JMicron USB 3 controller on the dock/enclosure; ASMedia is speculated to be less problematic. At any rate, "real world" experience finds dropped connection problems, which makes speed a secondary concern. Can this "dropped USB 3 connection" issue be addressed as well? Thanks.


    If SATA is set to AHCI it'll support hot-swapping if it's set to ATA/Legacy it will not.
  • 2 Hide
    ZakTheEvil , October 20, 2011 11:13 PM
    Oh crap, quoted the wrong post. This is such a crappy comments system: no edit capability :( 
  • 1 Hide
    Pyree , October 21, 2011 12:29 AM
    That is good to hear. I have used two different usb 3.0 controller and I don't notice difference on performance on mechanical HDD. Now that I know the performance is similar for different controller, I am thinking of getting SATA 3 external SSD.
  • 0 Hide
    livebriand , October 21, 2011 2:16 AM
    Is there a difference on USB 3/SATA adapters/enclosures? I have a WD Caviar Green 3.5" that the WD Elements USB 2 enclosure is bottlenecking (yeah, I know the newer ones are USB 3), and I'm wondering if the $15 Rosewill enclosure I'm looking at is good enough. Anything must beat the 25MB/sec I get currently though.
  • 0 Hide
    livebriand , October 21, 2011 2:18 AM
    zaktheevilUSB3 on my Gigabyte board was very unstable, hard drives would frequently disconnect. Disabling USB3 Power Management helped somehow, but they still often didn't appear after boot. I tried all available driver versions to no avail. I'm running Windows 7x64, by the way. Also, the enclosures I tried wouldn't spin the drives down after the host PC was shut down. I finally got two eSATA enclosures instead.

    USB 3 power management seems to cause issues. With it enabled, I got really slow speeds (using a USB 2 HDD though, just out of curiosity). With it disabled, I got the same speed as the USB 2 controller.
  • 0 Hide
    snorves , October 21, 2011 5:30 AM
    There is High Speed version of USB2.0 which allows transferring of data significantly faster than the standard version. In my previous PC, it was enabled only on a certain port.
  • 0 Hide
    SteelCity1981 , October 21, 2011 6:13 AM
    I don't see a big jump in performance on my USB 3.0 vs my USB 2.0 in file transfer using a External USB 3.0 hard drive I go from 20mb on USB 2.0 to 60mb USB 3.0 on acg sometimes it will go up to 80mb but i notice if I'm transfering a bunch of diff files my USB 3.0 transfer speed drops to almost USB 2.0 speed.
  • 0 Hide
    ArgleBargle , October 21, 2011 10:33 AM
    I have four external WD 3 Tb drives on USB 3.0, achieved with a four port hub plus a controller which plugs into the PCI 1x slot (motherboard does not have USB 3.0 native). I'm lucky if I can get 50 Mb/s sustained transfer from the internal HD to an external. It's about 2.5X as good as USB 2.0 sustained, but not too fantastic. Running Win7 Ult64 with 12Gb RAM and an i7-950.
  • 0 Hide
    ArgleBargle , October 21, 2011 10:37 AM
    lp231...basically the eSATA drive becomes a internal cause you lose the ability of hot plugging and swapping.

    I have an external drive which has eSATA, USB 2.0 and Firewire. I'm using it on USB 2.0 for this very reason: hot plugging/swapping.
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