4 Replies Latest reply on Jul 31, 2015 2:33 PM by Sam1978

    Z97 USB3.0 HDD disconnects; works on ASMedia USB3.0 ports


      I have the following system:


      • ASUS Z97-WS motherboard
      • Intel i7-4790K (not overclocked)
      • 16GB 1833MHz memory
      • USB 3 external disk docking station (BlacX 5G Duet)


      I use the docking station to swap out backup disks on a regular basis.  During a normal backup or archive operation, this is rock solid and very fast.  I'm quite pleased with performance.


      Retrospect has a "media verify" option, during which the program does the following:

      • reads every file from the backup or archive to ensure the file can be read successfully
      • If the file also exists in its original location on the source being backed up, it calculates an MD5 hash and compares it to the hash stored in the catalog


      A "media verify" is read-intensive, reading about 100MB/second.  With the docking station connected to one of the Intel USB3 ports, the disk will disconnect after reading 20-30 GB or about 5 minutes of continuous high read-only load, and then immediately reconnect.  If watching in Windows Explorer the drive disappears and reappears within about 10 seconds.  I have tested with a Seagate and a Western Digital disk and both exhibit the same behavior.


      To remove Retrospect as a variable I wrote a simple Java program (see attachment) which opens the raw disk device and reads the entire disk 128MB at a time.  This also fails within 5-10 minutes as the disk momentarily disconnects and reconnects.


      I did a lot of web research and determined it was probably a USB3 power management problem, so I:

      • Disabled "Allow computer to turn off this device to save power" in Device Manager for all USB hubs
      • In Power Options/Advanced Settings/Hard Disk, changed "Turn off hard disk after:" to NEVER
      • In Power Options/Advanced Settings/USB selective suspend, changed setting to DISABLED


      None of these changed made any difference.


      Then I remembered that the ASUS Z97-WS actually has a second USB3 controller, an ASMedia ASM1042 chipset, which connects to two of the six back-panel USB ports.  I moved the disk docking station to one of the ASMedia ports, and all the problems disappeared.  The simple Java test program runs to completion (all 2TB on the disk) and the Retrospect Media Verify operation completes successully.


      Is Intel aware of this problem? Is there a fix coming?  I have the current chipset drivers from Asus installed.

        • 1. Re: Z97 USB3.0 HDD disconnects; works on ASMedia USB3.0 ports

          Thanks for joining the Chipset community.


          Release notes for the latest USB 3.0 drivers do not indicate the problem you are reporting as an issue that Intel is aware of.




          Please make sure you have loaded the latest USB 3.0 driver here: Intel® Download Center



          • 2. Re: Z97 USB3.0 HDD disconnects; works on ASMedia USB3.0 ports



            I have two ASUS Z97-Pro (Wi-Fi ac) mainboards and on both similar problems as described above by jhgarrison. I'm using Win 7 Pro x64 and the latest Intel USB 3.0 drivers (


            Every external hard disk drives (and I have tried several different disks) which I connect to any Intel USB 3.0 ports on these boards are disconnected after about 1 to 2 minutes and immediately reconnected. This will continue for about 10 minutes and then sometimes instead of being reconnected Windows gives an error message claiming that the disk needs to be formatted and offering to format the disk. With some disks (Intenso) this happens right away when plugged into the USB 3.0 port, creating such error message once every second until the disk is unplugged again.


            All of these drives work flawlessly on any USB 2.0 or ASMEDIA USB 3.0 port of these mainboards, or on the Intel USB 3.0 ports of other mainboards with the exact same Intel drivers, such as the ASUS P9D WS with an Intel C226 chipset.


            Wi-Fi adapters, such as the Alfa AWUS036H or TP-Link TL-WN8200ND can be installed when connected to an Intel USB 3.0 port, but shortly after an successful installation of the drivers, the device disappears from the device manager. If unplugged and connected to an USB 2.0 port, they reappear immediately and work just fine.


            The UEFI of these ASUS Z97-Pro mainboards have an item called "Intel xHCI Mode" which can be found in the "USB Configuration" menu. The default setting is "Smart Auto". If changed to "Disabled" these problems all seem to disappear. The external USB 3.0 disks work fine (I have not tested the speed yet), and so do the Wi-Fi adapters. However, I have no clue what exactly I am disabling there and what consequences this could have for the system. Also, the same option exists on the ASUS P9D WS and work perfectly fine unchanged (Smart Auto).


            Does Intel have a clue what might be going on here?



            • 3. Re: Z97 USB3.0 HDD disconnects; works on ASMedia USB3.0 ports

              If you are saying that you disable this function through BIOS, this means that it might be an issue with BIOS configuration of Intel xHCI Mode, or USB 3.0 port.

              Possible BIOS update or contacting Asus for more information.



              • 4. Re: Z97 USB3.0 HDD disconnects; works on ASMedia USB3.0 ports

                Yes, I disabled this function through the (UEFI) BIOS. I updated the BIOS to the latest version, but the problem persists.

                I sent an email to Asus' support. If they come up with a solution I'll post it here.


                Thanks for the advice though. It did help me to further isolate the problem.