[kubuntu] two gpu two x servers, move mouse from one x server to the other

I have two GPUs, but enabling xinerama is bad, makes everything extremely slow.. So I thought I might use two x servers.. but I do not understand how I move the mouse courser from one screen to the other.

I can start program on the other screen using
konsole --display :0.1
and then the keyboard move to the other screen, but how do I move the mouse?
Thanks.