Laggy when primary screen is turned off?
 

Display link works fine for me (USB 3.0 using an i-tech docking station) on linux.

However, when I turn off the primary screen, the display link screen gets reeeeaaly slow and laggy (while still working otherwise).

Have any of you experienced the same? Could this be because somehow the graphics card is turned off, or the refresh rate changes, when the only "real" monitor turns off?