Motion Reprojection decreases FPS

User Support Hub Virtual Reality (VR)
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RTX3090, Ryzen 5950x, HP Reverb G2.
Using latest OpenXR Developer Tools for Windows Mixed Reality.
VR graphics settings in Flight Simulator similar to those in already published tips and guides.

With enabled Motion Reprojection in OpenXR Dev Tools, I get on average 30-35 fps, sometimes dipping below 25, sometimes up to 45.
With disabled Motion Reprojection, I get 40-45 fps, rarely dipping into 30s.

I have tried several times on same short flight, restarting PC after every settings change.

Is it expected for motion reprojection to take so much performance?

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I had similar experience. With repro enabled I see excessive mainthread frametimes compared to disabled. Submitted a bug with comparison screenshots during beta phase.

I find it frustrating that (particularly on YouTube) it keeps getting recommended to switch this on without raising awareness of this CPU overhead.

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Have you got Hardware accelerated GPU scheduling turned on out of interest?

I’ve found it causes massive instability with reprojection on the G2.

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Hardware-accelerated GPU scheduling is off.

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Same problem here. Motion reprojection is costing about 5 fps (RTX 2080 Ti)

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how you know your FPS on vr? i have the FPSVR but doesnt works when is not running the steamvr. Also what setting you have on openXR and on flight to achieve 40-45? I have a similar system.

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I was just about to create a topic on the same subject. I notice that I lose 5-10fps as well. Although motion projection is enabled, the fps are not at all stable and fluid like in DCS or X-plane as the frames jump around between 25-28 fps.

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There is option “Display frame timing overlay” in OpenXR Developer Tools for Windows Mixed Reality. When it is on, it shows a rectangle with fps in left eye display.

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Is the whole point is for motion reprojection to lock in on a lower FPS to allow from reprojection of frames? Should be 1/2 of the refresh rate of the goggles. The idea is to trick the brain into thinking you are seeing more frames then what you are. if you can’t hit 30fps then it does nothing for you. if you are between 30-44 then the headset should lock in on 30. If you are between 45-89 then you can get 45 and if at 90 you get 90. You will see your GPU utilization go down because it no longer is pushing the GPU to the max.

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The problem is that I can hardly even get stable 30fps with A320 at bigger airports with clouds and resonable resolution…In such case it’s better to turn it off to get higher fps. It works amazing under less demanding scenarios though:)
G2/5600X/32GB/RTX3070

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