Asynchronous reprojection
Warping the last rendered image to the freshest pose in a separate, high-priority GPU pass, so the headset always has a new frame to show.
The game's rendering and the reprojection run as separate tasks on the GPU. If the game misses its budget on one frame, reprojection steps in anyway and delivers a warp of the previous image at the panel's rate, instead of the whole view freezing — the difference between an unnoticed hiccup and a stomach-turning jolt.
Rotational warping (timewarp) is cheap and nearly exact; positional and motion warping (Oculus's "Asynchronous Spacewarp", Valve's "motion smoothing") extrapolate movement and can throw artefacts around edges that should have been disoccluded. The technique carries a different name at each vendor but rests on the same idea. Compare temporal reprojection, which reuses frames to save rendering cost rather than latency.