The load is dependent on the scene you're seeing and your settings. Generally, if you get x FPS from a scene in desktop mode, expect it to be half at least in VR mode.
A scene with 2 people can give you a good FPS output or terrible depending on a lot of factors, like how it's made, timing of hw demands, your hw and potential bottlenecks. GiveMeFPS is a plugin I used when I had a weak GPU, which gave me quick access to change quality settings of things like hair, lights, clothes, some of the big factors.
The biggest demand is likely soft-body physics, which is also the best feature of VaM. If your laptop can't handle soft-body physics in desktop mode, VR will be a bad experience overall, even with SBP off. You likely have a too weak of a computer to be able to handle more than the simplest of scenes with decent FPS. Of course, this can be compensated a little by reducing quality overal, that's where you can try the plugin I mention, but there'll be only so much you can do about it.
Btw, uncheck "high quality physics" because it doesn't mean what you think it means, only turn it on if the scene creator says you need it ON.