Unconstrained Framerate is the term for how many frames per second (FPS) the system is generating before sending them through the VR compositor. When enabled, SPS netted a 17.99% increase in average unconstrained framerate for the GTX 1080 Ti, while the RTX 2070 saw a 14.71% increase at High Settings, and 7.53% increase at Fast Settings.
Next, and perhaps the most important metric for VR users, is Average Delivered Frames. In the case of the Oculus Rift S, the goal is to deliver an average at or near a constant 80 FPS so as to prevent the HMD from engaging Asynchronous Space Warp and generating synthetic frames. VR is always at its best when it’s fast and smooth. Otherwise, when confronted with synthetic frames and stuttering, some may feel ‘VR sick’.
This time, under the new test conditions, average delivered frames for the GTX 1080 Ti showed a massive difference: With SPS engaged, the HMD saw an improvement of 36.67% in delivered frames. Additionally, the RTX 2070 benefitted with an improvement of 33.51% under High Settings, and 21.04% under Fast Settings.
Average Frametimes for both systems in all test parameters were either identical or within 2ms regardless of SPS mode.
Lastly, SPS again displayed a consistent and statistically significant benefit in Average Worst frametime (ms). For each of the GPUs and under both High and Fast iRacing settings, SPS On lowered average worst frametime by 30.8%, 47.38%, and 13.49% respectively, for an average reduction of worst frametime latency of 30.55%. With significant gains found across all metrics, it is confirmed: NVIDIA’s SPS does aid VR rendering in high-load, geometrically complex situations.