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.
As of this writing, the tool supports both the Oculus Rift and the HTC Vive via SteamVR. Like FCAT, FCAT VR can be used to measure both AMD and Nvidia GPU performance, though Nvidia recommends disabling a handful of settings on Nvidia GPUs if you're after true apples-to-apples benchmarking between the two companies' cards.
FCAT VR will be useful mostly for enthusiasts who want to quantify just how fast their computer is and for reviewers who are trying to get more in-depth performance information about specific games and GPUs. But it could also be useful for developers looking to optimize particularly demanding scenes so that they'll play well on hardware that meets Oculus' and HTC's minimum system requirements but without a lot of extra performance headroom. New software tricks have already allowed Oculus to lower the minimum specifications for a VR-ready PC, and this kind of thing means that thorough testing on performance-constrained hardware is important.
A more detailed guide on what the tool can do and how to use it is located here. Obviously, you'll need to have a VR headset if you want to give it a try.