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Old 10-24-2016, 09:47 PM   #1
ashic
Junior Member
 
Join Date: Oct 2016
Posts: 4
Default Very low fps on external Diplaylink monitor w 16.10 and 1.2.65 driver

I've commented on another post, but will create a thread here.

I have a Precision 5510, and connected it to a Dell monitor with both a Dell USB 3 dongle, and a Dell D3100 dock (which is "linux compatible". Even with the latest Displaylink drivers, I'm seeing terrible performance on the second monitor. However, if I connect the monitor directly to the laptop's HDMI port, everything runs fine. I've noticed the following:

1. Using bumblebee, running glxspheres on second monitor using Displaylink I get 1 fps when on intel graphics (both with Displayport, and HDMI connected to dock).
2. Using bumblebee optirun, I get 200fps.
3. Using bumblebee on the laptop monitor, I get 60 fps when on intel grpahics.
4. Using bumblebee on the laptop monitor, I get 200 fps when using optirun.
5. If I switch to Prime graphics using the dock, I get 2000 fps on the second monitor, but the internal monitor shuts off.

I've also run it using the open source drivers, and I get 60fps on the internal screen, but only 1 fps on the external one. Optirun doesn't work with the open source driver.

I'm currently running it with a seperate HDMI cable, which gives ok performance, but means the expensive D3100 dock is essentially a USB + ethernet hub; functionality which can be got from a £15 component. The same laptop runs when connected to an external 4K monitor using a Plugable thunderbolt 3 adapter, so I have to come to the conclusion that Displaylink just doesn't work. I recall having lag issues with this setup when on Windows... I thought that was Windows being buggy... I guess I'll try and see how the direct HDMI cable works there.
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