FCAT VR: GPU And CPU Performance in Virtual Reality

FCAT VR: An Illustrative and Accessible Tool For VR Testing

There’s a lot to like about FCAT VR, and a couple of improvements we'd like to see.

FCAT VR clearly gives us insight into graphics, host processing, and whole platform performance that we didn’t have previously, for starters. Yes, all of this data was accessible on the Vive through Valve’s SteamVR Frame Timing log and on the Rift via Event Tracing for Windows. But organizing it was a mess. We have pages of unpublished content in our CMS to show how quickly data becomes obsolete if you’re caught charting when a conclusion-changing driver is published. FCAT VR improves the rate at which we can collect data, get that information into a digestible format, and analyze it in a meaningful way. This alone should excite gamers who’ve bemoaned the lack of performance-oriented VR benchmarking.

We also have to applaud Nvidia for keeping FCAT VR freely available, modifiable, and redistributable. The very source of these tools means they’re under increased scrutiny (and rightly so). Putting them in front of the largest audience possible gives everyone an opportunity to validate their results.

The Tom’s Hardware team does enjoy one leg up. In addition to the FCAT VR tools, we also have the hardware and software infrastructure needed to intercept and record the signal coming from a graphics card before it’s displayed in a head-mounted display. Processing that information tells us the rate at which new frames are hitting the HMD. And when we overlay the FCAT VR results on top, it’s pretty easy to see how the two benchmarking techniques correlate.

There’s another interesting benefit tied to our hardware vs. software comparison: it’s possible to illustrate that 11ms isn’t an absolute threshold for rendering new frames at 90 Hz. Preemption and parallelization in the pipeline can buy precious milliseconds, and our video capture reports uninterrupted smoothness even when the software trace exposes brief incursions beyond 11ms.

In addition to its utility as a yardstick for evaluating graphics cards, FCAT VR also opens the door to evaluating other components under the duress of virtual reality. Dropping in a high-end graphics card and swapping CPUs in and out showed us that Arizona Sunshine really does respond to host processing performance—we’d like to see how other games scale based on core count and frequency. AMD’s Ryzen may give us the perfect opportunity to go into depth on the subject.

Of course, we also hope to see Nvidia continue FCAT’s development. The VR Analyzer needs more configurability, and our wish list already includes new background colors, specific dimensions for exporting charts, and an easier mechanism for altering the x- and y-axis. A reliance on runtime compatibility is worrying, but frankly somewhat unavoidable. So long as Valve and Oculus don’t deliberately impede FCAT’s functionality, future support shouldn’t be a problem. But we’ll cross that bridge when we get there. In the meantime, let us know what you think about FCAT VR, throw out some ideas for hardware comparisons, and suggest some games you’d like to see tested. We’re ready to get the data flowing.

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  • ingtar33
    no ryzen? just an 8320?
  • AndrewJacksonZA
    A really nice article and a great introduction to FCAT VR. Thanks Chris!

    Obvious request that probably everyone will ask of you: please include Ryzen in your tests once you have a sane moment after the hectic launch period. :-)

    Now that that's out the way, I can get to my actual question: I would like to know if "Game A" is available on both the Rift and the Vive, would FCAT VR be able to tell you what, if anything, the performance difference is given the same computer hardware please?

    Please can you also include multi-GPU setups. They can definitely help, depending on the title, e.g.
    https://www.hardocp.com/article/2016/11/30/serious_sam_vr_mgpu_nvidia_gtx_pascal_follow_up/5
    https://www.hardocp.com/article/2016/10/24/serious_sam_vr_mgpu_amd_rx_480_follow_up/

    I found this statement to be very interesting: "it’s possible to illustrate that 11ms isn’t an absolute threshold for rendering new frames at 90 Hz."

    Thank you
    Andrew
  • cangelini
    Hi guys,

    Ryzen wasn't in my lab yet when this was written, but I do have plans there ;)

    Andrew, yes, FCAT VR should allow us to test the same title on two different HMDs and compare their performance.

    Multi-GPU is a plan as well, particularly once games begin incorporating better support for it (right now, that's a bit of a problem).
  • WhyAreYou
    Thanks, looks good!
  • playingwithplato
    Do FCAT VR's measurement algorithms tend to favor NVDIA chipsets? Curious, wonder if AMD will release a similar testing tool to measure buffer store/retrieval and render speed <11ms? Would like to see that applied to en environment with their GPUs.
  • ffrgtm
    Fantastic article! I would love to see results with a secondary GPU (non-SLi) dedicated to physics and compare that to the cpu swap tests in AZ Sunshine you've just shown us.
  • ffrgtm
    159646 said:
    Do FCAT VR's measurement algorithms tend to favor NVDIA chipsets? Curious, wonder if AMD will release a similar testing tool to measure buffer store/retrieval and render speed <11ms? Would like to see that applied to en environment with their GPUs.

    A quote from another article on FCAT:

    Quote:
    "While the FCAT VR tool is developed by Nvidia, the company insists it is headset and GPU agnostic, and meant only to capture data. The tool itself doesn’t contain a benchmark; according to the company, the tool logs information directly from the VR runtime."


    I'm inclined to believe Nvidia's claim of brand blindness right now... but if AMD ever manages to put forth some real competition then I don't think we could be blamed for becoming more skeptical. It's hard to forget just how far Nvidia and AMD have gone to skew results in the past.
  • AndrewJacksonZA
    134065 said:
    Andrew, yes, FCAT VR should allow us to test the same title on two different HMDs and compare their performance. Multi-GPU is a plan as well, particularly once games begin incorporating better support for it (right now, that's a bit of a problem).
    Thank you.


    One thing that I might've missed in the article: Has Nvidia open-sourced FCAT and FCAT VR so that everyone can see the code, check it for unbiasedness (is that even a word? :-) and help contribute to the program to make it even better?
  • cangelini
    Yup, check it out: http://www.geforce.com/whats-new/guides/fcat-vr-download-and-how-to-guide

    There's a download link in there. I'd be curious to hear from any TH readers who want to mess with it as well!
  • thinkspeak
    Any chance of doing this again but with stock and OC on the maxwell, pascal and AMD cards? The 980 ti really opens up and they generally overclock well, in some cases exceeding the 1070 which would be useful for those debating an upgrading for VR
  • mitch074
    I guess my o/c'ed 4670k and reference RX480 should be able to handle this correctly, then... Now, if headset prices could go down!