VR shouldn't make you sick!
Every experience in VR needs to be optimized for comfort. During your next VR experience, verify that the images in the headset display with no lag or jumping when panning quickly or walking. In desktop VR, low frame rates - which manifest as judder or lag - are the primary cause of discomfort for users.
This means that for users who are sensitive, a more powerful graphics card and computer are the best way to prevent even momentary drops in frame rate.