USB Hub Power Mystery

Just received the 10 port USB hub. My question is … I have the following attached:

  1. 3 External USB hard drives (2x250GB Iomega and 1x1TB WD My Book)
  2. Microsoft Natural Keyboard
  3. Logitech Trackball
  4. HTC Imagio smartphone
  5. Garmin nuvi 255W

I also will be attaching a Logitech c510 webcam, Casio CD Label Printer, and a Verizon Wireless USB Aircard.

Ok … the issue is (which I have seen with other USB hubs also), when I turn the computer off, the three hard drives do not power down. The two Iomega drives have a power button, but pressing them also will not shut down the power to the drives.

I disconnected the power cord from the hub, and the drives would still not power down (my other USB hub that the drives were connected to “allowed” all the drives to power down if I disconnected the AC). I then disconnected the USB cord to the hub from the computer. Still, no power down.

AND … the blue LED strip was still lit – even with the USB cord disconnected from the computer and the AC disconnected from the hub.

I really need to be able to power down these drives without having to unplug them each time I close up for the night. Any ideas?

Great product regardless. Thanks! Be well,


Oh, and the computer – is a Dell XPS15 with 2 USB 3.0 ports and 1 USB 2.0 port. The hub is plugged into one of the 3.0 ports based on the configuration of my work space, cords, etc.

Hi Howard - Thanks for the question and the kind words about our product! Let’s see what we can do to untangle the mystery.

The Dell XPS 15 is running Win7, right?
Do one or more of the USB devices attached to the hub have their own AC power supply? Can you say which ones?

Let’s first see how USB selective suspend is set for the hub. If you can open the Win7 Device Manager, then go to View->“Devices By Connection” and then walk down a somewhat deep tree of devices PC->ACPI->PCI bus until you find the USB Host Controller that the hub is attached to.


Then right click on the “Generic USB Hub” which is the 10 port hub (note it may take some guessing if you have multiple hubs - look then at what devices are connected downstream to confirm. The 10-port hub is internally two cascaded hubs with Terminus Tech chips: 7 port and 4 port).

Then select the Power Management tab for the hub


Is the “Allow the computer to turn off this device to save power” option checked? If not, let’s go ahead and check it to turn on USB “selective suspend” (this feature allows the OS to power down individual USB devices that are not in use, even if busses/CPU higher in the tree are awake).

Thanks for replying with this info - then we’ll head into next steps.

Thanks again!

Ah - and I forgot to mention. You’ll want to enable selective suspend for both the 7 and 4 port hubs internally that make up the 10 port hub. And based on how you said you have the 10 port hub connected - through your USB 3.0 host controller, that may make it easier to find in the device tree.

Note, though, that one thing we’ll want to compare is the behavior on a USB 2.0 port and those USB 3.0 ports - they could very well be different, as there is a 3rd party NEC/Renesas driver involved for the USB 3.0 ports, that could change behavior …

Here’s to solving the mystery(ies),

I have attached a screenshot of my device tree. It looks as if the devices are attached through a USB 3.0 hub. None of the “hubs” had power management options. The two Generic Hubs further down did, and they were already checked. Very impressed at the quick response! Thank you.

Any thoughts based on my screenshot?


Yes … Win7 Ultimate 64-bit

Ok, one more thing to add …

I plugged the three external drives and the 10 port hub into it’s own power strip (which is actually plugged into a backup battery). Turning off the strip will power down the drives. BUT, the LED strip on the hub still shines. And, even when I disconnect the hub from the computer … the LED still shines? Does this unit have its own backup power? Thanks …

Hi Howard,

Thanks for the quick replies!

  1. On the magical mystery LED - nope, no battery in the hub. With both hub AC power and upstream connection to PC disconnected, I would assume power is coming in the form of back-voltage from a downstream device. This won’t hurt the hub (it’s designed to handle power for many USB devices after all), but definitely could light an LED (it doesn’t take much power). Might you have any downstream devices or hubs which are AC powered that could be lighting the LED?

  2. It sounds like you have a good solution with the power strip, but in terms of making sure Windows is doing everything it could to power down devices automatically, next steps would be two things:

2a) Move the 10 port hub over to USB 2.0 and see if we can get the powerdown behavior we want there first (using an all-Microsoft USB stack), before then moving over to USB 3 (where Renesas 3rd party drivers are loaded for parts of the USB stack). Once you’ve connected via USB 2.0, my earlier instructions above should apply for turning on selective suspend

2b) Once we move back to USB 3.0, the Power Management tab should be there, but the hub has a different name. Look for “Renesas Electronics USB 2.0 MTT Hub” – that’s what the Renesas driver will report for hubs. The properties on that will have a Power Management tab as described above.

Thanks for your patience working together with us to have a solution to meet your needs,

Ah, the “Generic USB Hub” down lower isn’t the 10 port hub - it’s something else. Since you’re connecting through USB 3.0, the 10 port hub is the (only) one called “Renesas Electronics USB 2.0 MTT Hub”. Look for the power management tab there. Thanks!

Hmmm … once I cut the power to the hard drives, the only devices left are the keyboard, trackball, and smartphone. Could the smartphone actually cause the LED to remain on? I will conduct the other experiment over the weekend when I have bit more time to play. Thanks!

I don’t have power management tabs for USB 3.0 under device manager. 2.0 ones have it, but not the 3.0 ones. My Seagates aren’t behaving nicely with this. Annoyed.

Hi Benjamin - USB 3.0 stacks (from Renesas, Intel, VIA, etc. ) must replace Microsoft’s hub driver (usbhub.sys) with a USB 3.0 aware one – and these 3rd party drivers will have different functionality. This is a function of the USB 3.0 software stack you’re running.

Let us know if you’re running any Plugable products If so, we’ll help understand any problems that come up. Best wishes, Bernie.

Thanks. I’m using the latest appropriate Intel USB 3.0 extensible & host drivers, and iusbmon3.exe is also running in the background. I’ve tried the original motherboard drivers for this and the latest direct from Intel’s site. The problem is there is no power tab at all inside the USB 3.0 panels in Device Manager. I even tried the MicrosoftFixit50052 for turning off all USB power management. And Seagate’s Dashboard Power setting doesn’t even seem to have an effect. Are these “stacks” interchangeable between the brands, or are they specific to the hardware?

Hi Benjamin - The interface to USB host controllers is through the XHCI standard (0.96 or 1.0). With Windows 8, Microsoft’s built- stack will talk with most USB 3.0 host controllers on the market today. But on Windows 7 and earlier, you must use the 3rd party stack of the host controller you have. They’re not interchangeable. In your case, it’s the Intel provided USB 3.0 stack.

You don’t have any Plugable products in the mix, so there’s really nothing more we can help with here, but I’d recommend you look for forums which discuss the Intel USB 3.0 stack, for info on what it can and can’t do for power management.

Wishing you the best - Bernie