Ubuntu 16.10 + Displaylink + External monitor is slow on intel HD graphics - Ask Ubuntu

i've got dell precision 5510 (skylake) hooked external monitor via displayport (though same problems came hdmi) using 2 different displaylink docks. when on intel graphics, framerate on external monitor appalling - around 1fps when running glxspheres. using optirun, it's way more (200 fps, same on laptop monitor). if switch nvidia prime graphics, laptop monitor shuts off completely, external monitor performs (2000+ fps).

using intel graphics, chrome became unusable on second monitor, until disabled hw accelration in chrome settings, when became quite usable. big problem i'm facing terminal on external monitor extremely laggy due 1fps problem. there way overcome problem, or disable hardware acceleration entirely; have tonnes of cpu spare.

update: appears if connect monitor hdmi cable directly (instead of through either of displaylink docks, second monitor gives 60fps using intel graphics. mean running cable, guess that's i'll have now.

i myself not linux guru other people here, found @ least worked me:

• go /etc/x11/xorg.conf.d/ (or create said folder)
• search if have *-intel.conf file
• if yes, add line before endsection: option "vsync" "false"

• if no, create file 20-intel.confand write this:

  section "device"     identifier  "intel"     driver      "intel"     option      "vsync" "false" endsection 

• reboot

this should force intel driver stop vsyncing displaylink monitor 1fps.

again think not competent enough assess situation why issue in first place , workaround may break other stuff. take here care!