VR owners, how are you dealing with fixed refresh rate displays?

[PainkilleR]

After reading Valve Index specs carefully I realized that the headset has standard non-variable refresh rate displays.

HL:A looks way too good to be able to maintain 144fps 100% of time even on 10/20 Nvidia series.

Any dips below target refresh rates cause stuttering. So my question is how are you dealing with framerate drops in VR? Does Valve Index have any mechanic to compensate framerate drops or something? Or does it have a default double/triple buffered v-sync?

[β312]

Index has support for 90hz, 120hz and 144 hz refresh rates(I have mine set to 120hz right now, 144 is really light games and more just future proofing). Plus steamvr has ton of things implemented like asynchronus reprojection -- that's what is going to smooth out the dips.

[SantanzChild]

You just set a lower refresh in the steamvr settings

[8Beet]

SteamVR uses a method called reprojection that attempts to hide frame drops by reusing frames when frames drop to help avoid discomfort in VR. It's effectiveness varies between people, I am mostly fine with reprojection. If you do notice a lot of reprojecting you can just modify the refresh rate and the render resolution of the index. (quick edit: this is done inside steam VR settings menu)

On my system which is moderatly spec'd in terms of VR using a valve index (GTX 1080, i7 6700k @ 4.4Ghz) my sweetspot is 100% renderscale at 120hz. For poorly optimized games like VRChat I do lower my refreshrate to 90hz. To be fair, that game doesnt run well on most hardware setups in VR lol.

[Chaunsey]

you can choose 80, 90, 120, or 144 FPS modes.

but frames dipping under the target is not noticable until it drops to low frames.

there are motion smoothing functions built into steamVR however, because when a game gets choppy in VR, without motion smoothing your view can stutter.

the software however inserts extra frames so that even if the FPS changes, your view remains smooth even in motion.

there are also functions to scale resolution up and down for every individual program, so if you can run one game at like 200 FPS, but you're playing at 120hz, then you can turn up the resolution to improve the visual fidelity. if another game you're chugging and can get only 70 frames at 1.0 resolution, you can cut it down to 0.9 to make your frame rate more steady.

you can also turn on dynamic resolution scaling, where steamVR will actually adjust the render scale automatically based on your performance and frame rate target.

[PainkilleR]

Originally posted by LlamaLlamaLlamaLlamaHeckYou:

SteamVR uses a method called reprojection that attempts to hide frame drops by reusing frames when frames drop to help avoid discomfort in VR. It's effectiveness varies between people, I am mostly fine with reprojection. If you do notice a lot of reprojecting you can just modify the refresh rate and the render resolution of the index.

On my system which is moderatly spec'd in terms of VR using a valve index (GTX 1080, i7 6700k @ 4.4Ghz) my sweetspot is 100% renderscale at 120hz. For poorly optimized games like VRChat I do lower my refreshrate to 90hz. To be fair, that game doesnt run well on most hardware setups in VR lol.

How well does reprojection hide frame drops compared to g-sync/freesync methods? Any framerate related artifacts be it stuttering/tearing are extremely noticeable to me, so should I ignore current "gen" vrs?

[SantanzChild]

Or just change the refresh as already stated.

[8Beet]

Originally posted by PainkilleR:

Originally posted by LlamaLlamaLlamaLlamaHeckYou:

SteamVR uses a method called reprojection that attempts to hide frame drops by reusing frames when frames drop to help avoid discomfort in VR. It's effectiveness varies between people, I am mostly fine with reprojection. If you do notice a lot of reprojecting you can just modify the refresh rate and the render resolution of the index.

On my system which is moderatly spec'd in terms of VR using a valve index (GTX 1080, i7 6700k @ 4.4Ghz) my sweetspot is 100% renderscale at 120hz. For poorly optimized games like VRChat I do lower my refreshrate to 90hz. To be fair, that game doesnt run well on most hardware setups in VR lol.

How well does reprojection hide frame drops compared to g-sync/freesync methods? Any framerate related artifacts be it stuttering/tearing are extremely noticeable to me, so should I ignore current "gen" vrs?

It's a different kind of tech, it hides it pretty well. When you notice it you really just notice that some of the sharpness of what you are looking at is lost for a few seconds or however long you are reprojecting. I honestly didn't even notice it until someone explained it to me.

[Chaunsey]

Originally posted by PainkilleR:

Originally posted by LlamaLlamaLlamaLlamaHeckYou:

SteamVR uses a method called reprojection that attempts to hide frame drops by reusing frames when frames drop to help avoid discomfort in VR. It's effectiveness varies between people, I am mostly fine with reprojection. If you do notice a lot of reprojecting you can just modify the refresh rate and the render resolution of the index.

On my system which is moderatly spec'd in terms of VR using a valve index (GTX 1080, i7 6700k @ 4.4Ghz) my sweetspot is 100% renderscale at 120hz. For poorly optimized games like VRChat I do lower my refreshrate to 90hz. To be fair, that game doesnt run well on most hardware setups in VR lol.

How well does reprojection hide frame drops compared to g-sync/freesync methods? Any framerate related artifacts be it stuttering/tearing are extremely noticeable to me, so should I ignore current "gen" vrs?

i have no used gsync or freesync, but essentially these are methods to sync up the frame timing between a monitor and GPU.

this is necessary because traditionally monitors just basically take the frames as they come, so they had to build in a module in the case of gsync for example, to handle the frame timing.


with VR the "monitors" are built into the headset and the frame timing is already carefully controlled, because for example, the index and many headsets have 2 screens, and these have to be perfectly in sync or your vision would be a mess.

further more, VR screens use ultra low persistence panels, the index in particular has as low as 0.3ms persistence displays.


screen tearing and stuttering is much worse in VR, so these are things they've had to handle.

so even if for some reason a game you play is performing badly, your actual vision should remain smooth.

[PainkilleR]

Does somebody know where can I read more about asynchronous reprojection? Wiki has very simplistic explanation and no tech info whatsoever. Or maybe somebody could explain to me how does it work in a greater detail?

[Scrooge]

It works by replicating the previous frame, but moving it in your field of vision in co-ordination with your movement. It allows the game to render at half frame rate, whilst displaying full framerate in the headset. It does however produce visible articfacts as the frame is just recycled and adjusted to your position.

[PainkilleR]

Originally posted by Scrooge McDuck Jr:

It works by replicating the previous frame, but moving it in your field of vision in co-ordination with your movement. It allows the game to render at half frame rate, whilst displaying full framerate in the headset. It does however produce visible articfacts as the frame is just recycled and adjusted to your position.

And what about controls? Will the input data be processed at half frame rate as well, or do controllers act similarly to mouse raw input method?

[Scrooge]

I'm not sure about the controls, as far as i'm aware it's only visual latency rather than input lag. If there is any input lag from controls it's imperceptible to me.

[CMDRZOD]

Its called async reprojection. Once the FPS drops below the target, the VR environment (SteamVR, OculusVR) will begin to create frames based on the last one, if a new frame is not ready from the GPU.

This tends to make games run at 1/2 the target display Hz. It doesn't look as good as a real frame but it greatly improves stuttering and jankiness.

Steam and Oculus both have their own version of this system.

[rusty_dragon]

Originally posted by PainkilleR:

Originally posted by Scrooge McDuck Jr:

It works by replicating the previous frame, but moving it in your field of vision in co-ordination with your movement. It allows the game to render at half frame rate, whilst displaying full framerate in the headset. It does however produce visible articfacts as the frame is just recycled and adjusted to your position.

And what about controls? Will the input data be processed at half frame rate as well, or do controllers act similarly to mouse raw input method?

Controls are not tied to fps. They have actually zero input latency, and have zero impact on computing performance.

But with all said above maintaining high framerate is required to be able to play VR games. Otherwise you would feel sick and low framerate destroying magic of VR, effect of presence and immersion. It's physically impossible to play a VR game with like 15 or 30 fps. Unlike how people can play this way on the flat screen.

But same time you don't need 2080ti to play VR unless you want super crisp image with high resolution.

Main performance hog and graphics quality option of VR is resolution(of rendered image).

[DCBenton]

They use something called asynchronous re-projection, Oculus call it asynchronous space/time warp.

https://en.wikipedia.org/wiki/Asynchronous_reprojection

Oculus explanation.
https://developer.oculus.com/blog/asynchronous-timewarp-examined/