High-end VR headset manufacturers like Oculus and HTC all publish recommended specifications for PCs that will run VR games well. But as with regular PC games, VR games will often use different engines and provide different levels of detail, and some of them will push those recommended specifications harder than others. To help measure and analyze performance, Nvidia today released a new version of its FCAT benchmarking tool, predictably named FCAT VR.
Like the standard FCAT (short for Frame Capture Analysis Tool) application or the classic FRAPS, FCAT VR is a utility that runs in the background as you run games. It captures data that can be saved as a CSV file for later reference, and the tool itself also includes some basic graphs you can use to visualize the data. The tool tracks the framerate delivered to your headset, the "unconstrained" framerate that the hardware would be capable of hitting if not constrained to the refresh rate of the headset, the number of dropped frames, and the number of synthesized frames (essentially educated, extrapolated guesses about what the next frame should look like) created by the system to prevent the appearance of dropped frames.
from Nvidia releases FRAPS-like tool for benchmarking and analyzing VR performance