Xorg works only when bbswitch is ON?

I've got a weird problem. I installed bumblebee and when I start Xorg with startx it freezes the system completely (cannot switch tty or REISUB). But, when I use bbswitch to turn my dedicated graphics card ON startx **does** work and, seeing the differences in fps when running glxspheres64 and optirun glxspheres64, it looks like bumblebee does work correctly. I thought this should work even when bbswitch is OFF because bumblebee will start the dedicated graphics when necessary? My system: - Model: Asus N551VW - OS: Arch - CPU: Intel i7 6700HQ - Dedicated: Nvidia 960m