VR generally requires an expensive and impressive PC, but Steam VR 'Motion Smoothing' is a new feature that aims to give lower-end PCs the ability to deliver VR experiences more smoothly. Functioning like Motion Smoothing for TV, this new Steam VR feature determines when an experience is lagging or dropping frames. From there, the feature automatically kicks in and drops the framerate from 90FPS to 45FPS while generating a mimicked frame to make it look like 90FPS.
While the feature will work on the HTC Vive or a Vive Pro, the Steam VR Motion Smoothing feature will not be available for the Oculus Rift or Windows Mixed Reality headsets. The feature is still in beta at the moment and can be turned on or off through the 'Tools' section on the Steam desktop app.