Large MSAA performance cost on UE5.1.1/WaveVR 5.3.0

[ericw]

Hi,

I'm seeing a large slowdown when enabling MSAA on the Focus 3 with UE5.1.1 + WaveVR 5.3.0. Focus 3 OS version is the latest available today, 5.0.999.812.

Steps to repro:

1. download WaveVR 5.3.0 (UE 5.1 build)
2. open the plugin.uproject demo
3. go to UE Project Settings -> MSAA Sample Count -> 4x
4. package and install build on Focus 3
5. launch VRTestApp
6. go to 202 Foveation Test and click on Ball Room -> Load Level (I'm not looking at the foveation here, which is disabled by default due to having Mobile Multi-View enabled, but just using this as a GPU test scene)
7. average FPS is ~33 (=30.3ms)

For comparison, change UE Project Settings -> MSAA Sample Count -> 2x

• average FPS is ~45 (=22.2ms)

For comparison, building the demo project from without any modifications (omit step 3 above):

• average FPS is ~65 (=15.4ms)

So, frame time doubles when moving from no AA to 4xaa. 

 

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On my project, we were previously using UE4.26.2 with WaveVR 5.0.2. I've re-tested the same scenario as above with those software versions and get the following: (note, I disabled foveation in the UI of "202 Foveation Test" for a fair comparison against UE5.1.1)

- 4xMSAA: 39fps

- 2xMSAA: 52fps

- No MSAA: 70fps

So it's still quite a large cost for AA in these versions.

Is this the expected performance cost of AA? Any suggestions for getting better performance with AA on? Thanks.