Tuesday, February 14, 2012

XPS15z: USB 3.0 incompatibility and problem with external hard disks

Dell XPS 15z laptop's USB 3.0 ports does not work with at least one USB 3.0 external hard disks out there; Toshiba Canvio 1 TB USB 3.0 portable external HDD.

Check the Dell forum for the details of the problem.
XPS 15z laptop USB 3.0 problem

The hard disk works fine with the USB 2.0/eSATA combo port at USB 2.0 speed. (~30MB/s). The hard disk is not recognized at the USB 3.0 port. When I plugged it, the hard disk blinked with blue light continuously and nothing happened. The same HDD gives around 90 MB/s data transfer speed in my Desktop's USB 3.0 port indicating that the hard disk works fine.

So far, the mother board has been replaced and that didn't fix the problem. A newer laptop also had the same problem. It appears to me that the USB 3.0 port does not provide sufficient power to such external hard disks. To test this, I purchased a cheap USB split Y power adapter cable and plugged the external hard disk to both of the USB 3.0 ports at the same time; the additional plug is expected to provide the extra power to the hard disk. My suspicion was right; now the hard disk is recognized by Windows. Since the split cable I bought supported only USB 2.0, I get only about 30 MB/s speed. 

Now one option for me is to get a USB 3.0 power adapter split Y cable if I need the super speed with this hard disk, which is about three times of the USB 2.0 speed in real life. Three times speed is useful if you have huge data to transfer; say you'll be done in 20 minutes instead of 1 hr.

Is it a design flaw from Intel in manufacturing such a motherboard? Is it Dell's fault in not disclosing this potential incompatibility to the customers when advertising USB 3.0 as a specification of the laptop? Or is it a problem from Toshiba in making a power hungry external hard drive? Who sets the standards for USB 3.0 power specification and requirements? (if there is such a standard).

I've no idea.
Update on April 18th 2012

Previously, I reported that the drive works with USB 2.0 Y split cable. It could transfer files in USB 2.0 high-speed (~30 MB/s) from that connection. But to get the USB 3.0 super-speed (~90 MB/s), I purchased a USB 3.0 split Y cable from Amazon.com. As I expected, the drive did work this time with USB 3.0 transfer rate. The problem is solved. But two of my USB ports are gonna be occupied if I want USB 3.0 speed. Well, at least it works. So finally, the problem seems that either the Dell XPS 15z doesn't provide sufficient power to the USB Hard disk or this specific USB hard disk is under powered from a single USB port. 

Hey, Dell, Intel, Toshiba....who is ready to take the responsibility?



  1. Ah! that is a good question.

    It is a shame that Dell made you run the hoops...and your taking the issue all the way up is commendable!

    Simpler solution for them would've been to send you a compatible Portable HDD before you went upstairs :) ... but of course that would mean that they accept the issue!

    I got a Western Digital Passport Portable 1 TB drive and it works fine with my Dell XPS 15z...my only issue was the speed...which was at mid 40's (although HD Tune scores at 80's)

    1. Did you mean your USB 3.0 WD external hard disk works fine at USB 2.0 speed in USB 3.0 port of your Dell XPS 15z? Interesting.

      Ya, I had to spent a lot of time related to all these issues. Dell technical support was pathetic. I'm glad that I escalated the issue. The problem could be from the Intel motherboard. So I can't blame it entirely on Dell until I confirm the reason.

      The explanation I received was that "Dell is aware of incompatibility of some external hard disks on USB 3.0 ports of XPS 15z laptop and Dell engineers are currently working to find a solution"

      I would have bought WD Passport external hard disk, but I got Toshiba on a deal and thought not to pass that one.

  2. Hi, I'm having the same problem with my Dell XPS 15z, the Canvio I have is not detected, when it is detected the driver failed. I tried it on another Dell product, the Inspiron One and it worked fine, and also tried it with a Toshiba notebook, again it worked OK.

    The thing is I'm in Indonesia and Dell does not have the support as where you are, I am hoping that this can be fixed somehow, I would still opt for Dell product.

    Also, I might try the option of getting a USB 3.0 power adapter split Y cable, but the speed would be different right?

    Anyway, the article helped, thanks a bunch.

    1. Thanks Harry for posting your experience. Sorry to hear that there are many disappointed Dell customers all around the world.

      I'm not sure whether a USB 3.0 Y-splitter cable will solve the problem. (see my reply to Terry) But it's worth trying. Probably Dell engineers should test them and provide an explanation and workaround for the issue. Till then, the option is to use the drive at USB 2.0 speed at 15z's eSATA combo port.

  3. Since I was helping someone with one of these.. what's the power consumption show in device manager under the USB Hubs? I wonder if it is the device demanding more power than the system will give or something else..

    1. Hello Terry, Thanks for your effort to find a solution to this annoying problem.

      The device shows 500mA in the 'Generic USB root hub'

      I noticed another thing today:

      1) If I plug only the main USB male plug of the Y-splitter cable to USB 3.0 port, the device blink continuously and is not recognized

      2) Now I plug the power assistance male plug to the second 15z USB 3.0 port. The device is recognized (as USB 2.0 device since the cable support USB 2.0 only)

      3) Further, if I unplug the power assistance cable leaving only the main USB cable plugged in to 15z, the device is still recognized. I can still access the drive. So it seems the power is sufficient from a single USB 3.0 port of 15z once the drive is initiated and recognized by windows. Hmmm...
      What does that mean? USB 3.0 Driver problem?

  4. Experiencing the same problem on a recent XPS 15 machine.
    My Western Digital Elements HD is capable to get ~120 MB/s on other hardware (with similar SSD as in the XPS15)

    Going on the hypothesis of lack of power: see slide 26
    "USB 3.0 delivers more power un-configured device or suppended device configured devices (USB 2.0 100mA-500mA) (USB 3.0 150mA-900mA)"

    Not really sure what this means, but the numbers seem to speak for themselves: a shortage of 400mA on the ports ...

    1. Thanks for sharing the info. Yes, it could be. But I too cannot make any authentic conclusion on the power rating/usage. From a practical point of view, power usage seems to be the problem. This issue is quite confusing since different users report different experience.

      Mine is HDD 7200rpm. Copying files in the same HDD gives 90 MB/s speed for me. So I guess that's the max speed I can get on this laptop with HDD.

  5. Hi,

    I can confirm that the problem is somewere related to power consumption.
    Had the same problem Dell XPS 15z with Toshiba Canvio 1GB.
    Using a USB 3.0 hub with external power supply all work fine now. Getting now data transfer rate ~56MB/sec.

    1. Thanks Martin for the feedback. Good to know it's working for you.

  6. Have to thank you too, I was going to the 'driver' way.
    You saved me a lot of work!


  7. I have a problem with WD MyPassport SE 1TB, when I connect it to my MSI GT70 USB 3.0 port if fails with windows 7 backup creating a system image. I have the same problem with my DELL XPS8300 with a Renesas (NEC) USB 3.0 controller, even if on the desktop the problem is more intermittent.
    I never had this problem with the older WD MyPassport 750GB.
    I assume this drive sucks more power.
    The error ix 0x80070002 and then the drive disconnects and reconnects immediately after the error.
    The only way around the problem was using a USB 3.0 hub with it's own power supply.

    I'm sure there are specification about power consumption on USB3.0, but apparently they are not enforced by the manufactures.

  8. which cable did you buy? i can't find one :(

    1. Any A to Micro-B USB 3.0 Y Cable should work. This is the one I bought. It's still working good.