UD3900 and Windows 8.1

I’ve been using the UD3900 with my Lenovo Yoga 11s for the last 3 weeks and it’s been great. I have an Acer monitor connected with HDMI cable, a Logitech wireless keyboard/mouse, and Ethernet, and up until 8.1 everything seemed great.

After the 8.1 update, it feels like the display and mouse are laggy, in a way that I did not notice before. Dragging windows around on the external monitor seems choppier, rendering of Aero-peek views seems slower, and the mouse seems to lag every so often.

It’s hard to know if this was happening before or if it really just started with 8.1, because I just haven’t had the setup for all that long. So I was wondering if anyone else is having a similar experience. I did update the drivers to the latest, so that shouldn’t be an issue.

Is there a way to test video performance with the UD3900 so I have some numbers for comparison?

Follow-up info: I did install all the Lenovo drivers that were updated for 8.1, but it does not seem to make a difference. There is definitely something ‘off’ about the video performance on the external monitor. If I start scrolling too fast, the screen will drop into a fuzzy-render and then will catch up. I never saw this happen under 8.0.

Hoping that DisplayLink will be able to improve the performance back to where it was prior to 8.1; it’s disappointing because everything worked so well in Win8.0

Hi Brian,

Thanks for contacting us, and thanks for the update! We’re also just getting calibrated to the subtle differences between 8 and 8.1.

We hadn’t yet seen a system where video performance noticeably dropped from 8.0 to 8.1, but it may be we missed it or didn’t have the right system.

Would you be willing to send your debug logs to us? Here’s how:

We’ll be able to look at the system details (driver versions, etc) for any possible causes.

Thanks again!

Thanks for the reply; should I send zip file to support@plugable.com?

Hi Brian - Yep, that’s right. If you include a link to this thread, we’ll know to connect the two together in one ticket. Thanks!

Thanks, sent.

OK, I think I have found something.

The Lenovo Yoga has several configurations; the one I use when attached to the UD-3900 is to have the keyboard flipped under and the display flipped up in a “stand” so I can use it as a second monitor. When you do that, the Yoga turns off the keyboard & touchpad so they don’t get accidentally pressed.

Just for kicks, I decided to flip the keyboard back around and try using the touchpad on the laptop to move windows around on the extended monitor. Surprise: the laggy window dragging and rendering is gone. And then when using the wireless mouse lag is still gone. Strange.

I thought maybe it was an incompatibility with the Logitech wireless USB keyboard/mouse itself, so I disconnected. However, I also have a BT Microsoft mouse, and it does the same thing: With laptop keyboard flipped back & disabled, window drags & peek renders lag. As soon as I activate the touchpad, lag is gone, and the BT mouse behaves better.

So, it seems to be some kind of interaction between the automatic disabling of the Yoga’s keyboard/touchpad and any external mouse. I will try to see if I can narrow it down with some additional experiments…

More clarification: the interaction is between the mode switching of the Yoga, the external monitor plugged into the UD-3900, and an external mouse. There is never a lag problem on the laptop screen, whether in stand mode or not.

I’ve also tried disabling the touchpad manually and then folding the keyboard back to switch modes, but it does not make a difference. As soon as the Yoga switches modes (disables keyboard/mouse), video performance on the external monitor goes downhill.

Hi Brian - Thank you!! These extra details are a great help – in combination with the logs (which we got, thank you), we’ll try to track down what Lenovo is doing differently in these different modes on the Yoga.

A bit more info:
I tried connecting my monitor directly to the HDMI port of the Yoga, and it behaved normally (no lag) in both modes.

Then I tried connecting through the DVI port instead of HDMI on the UD-3900, and I got the laggy behavior in “stand” mode, and normal behavior in laptop mode.

Finally, I tried connecting a wired USB mouse directly to the Yoga, (with monitor connected to UD_3900) and it behaved the same as the wireless USB mouse through the UD-3900 and the BT mouse – lag in stand mode, normal in laptop mode.

Let me know if you’d like me to try any other configurations.

I tracked this problem down a bit, and I’ve found that it does not actually have anything to do with the UD-3900. It’s the Intel Dynamic Platform and Thermal Framework. Here are the troubleshooting steps I took:

First of all, if you want to see the problem in action, just open up the Task Manager, and click the Performance tab. At the top you’ll see the CPU with a GHz number. Now, keeping Task Manager open, start playing a video and you should see the GHz number climb up to maybe 0.60-0.80 GHz. Still while the video is playing, flip your Yoga back into stand mode. You will see the GHz drop and the number will stick at 0.42 GHz – that’s the throttling that comes from the Dynamic Platform and Thermal Framework.

So I tried the following:

  1. Uninstall the DPTF from Programs and Features. I had version installed, which I had gotten from the Lenovo website.

  2. Restart machine. Voila – no more throttling.

  3. Reinstall that same version. I thought maybe doing a complete uninstall and reinstall might make a difference.

  4. Restart machine. Back to 0.42 GHz

  5. Uninstall DPTF & restart (no more throttling)

  6. Install version, which is on my D: drive in the Drivers folder. Presumably the version that my machine came with.

  7. Restart machine. Back to 0.42 GHz :frowning:

  8. Uninstall & restart

So, this leads me to believe that there was some configuration of DPTF that is outside of the driver install, and it got overwritten by the 8.1 install. The other possibility is that we were always running at 0.42GHz in tablet mode, but something about 8.1 uses way more processor, so we now see issues. I guess if we could get someone with 8.0 and no issues to check this for us it would be another clue.

At this point, I’ve reinstalled the latest DPTF driver, but I’ve disable DPTF in the BIOS. Hopefully Lenovo will have something to say about this at some point. I do not know if there are any other implications for disabling this, but I have to say, my computer has been running great without it.

Brian - thanks again for this update and solution to uninstall “Intel Dynamic Platform and Thermal Framework”


Thanks for this post. It worked for me too. Yoga 13 bent backwards, UD-3000. Before your fix Excel was a dog under Win 8.1, now it runs as fast as ever.

One question. What does the DPTF driver do? I assume it is managing heat inside the machine and when bent backwards and assumably sitting on a desk or your lap, the machine can’t vent heat as well through the keyboard. I am trying to create an air space under my Yoga just in case.


Howard, I am a little concerned about this too – how and why does the Yoga use the DPTF? As I was investigating, I found this thread in the Lenovo forums:


There is a comment in there by “Andy1990zx,” who is marked as a Lenovo employee where he seems to say it’s not being used for a thermal issue, Unfortunately he doesn’t give more detail.

Since I already own the Yoga and like it, I’ll live by Neil Young – “It’s better to burn out than fade away.”