Rift and V-Sync

[pirsquared]

I noticed that a lot of suggestions for the Rift seem to involve turning off vsync and I was wondering why this is the case? I'm presuming it's because when fps drops below 60, vsync will drop the fps to 30 and the sudden drop would be detrimental to the experience etc. If that's the case, then wouldn't adaptive vsync be sufficient? That would allow both the screen tear prevention and reduce stuttering when fps drops

[Namielus]

Oculus recommends Vsync on now.

[pirsquared]

Does TF2 still recommend vsync off? I guess my question would be better stated as : Is there any downside to using adaptive vsync with the rift?

[jf031]

Vsync adds latency, especially at the low rate of 60Hz (~16.67 ms per update). The reason why it adds latency is that it buffers all the pixels that make up the screen (I'm not technically knowledgeable on this topic, so sorry if I'm using the wrong terms, etc.), then renders it all at once, in time with the monitor's refresh. With vsync off, when the pixels are processed, they are sent to the screen ASAP (I guess). This causes tearing, since the pixels are not being updated in sync with the monitor's refresh. Also, for whatever reason(s), many games add considerably more than just 16.67 ms of latency with vsync on.

A 120Hz screen should be the minimum for the consumer Rift.

[pirsquared]

Hmm, that makes sense but if so why does Oculus now recommend vsync on? I suppose they feel the screen tearing is a bigger issue?

[kludd70]

I'll take anything over tearing. Even on my monitor it's unbearable, I can't imagine how awful it would be on the rift.

[MrGreen]

I'll take anything over tearing. Even on my monitor it's unbearable, I can't imagine how awful it would be on the rift.

Tearing is tear-ible (sorry) but the input lag v-sync adds is easily perceptible with a mouse, I can only imagine how unbearable it must be for head tracking.

Abrash is right when he says we have a long way to go...

[Fluke]

Hmm, that makes sense but if so why does Oculus now recommend vsync on? I suppose they feel the screen tearing is a bigger issue?

They always have recommended vsync on from the beginning - Palmer mentions it in pretty much any video where he talks about what you need for a solid VR experience.

It's Valve who are being contradictory in saying that vsync should be off in TF2.

[Pyry]

Has anyone actually complained about head tracking latency with the Rift? The main complaints I've seen are about the screen door effect and the motion blur from the slow pixel response time. In contrast, everyone seems to praise the responsiveness of the tracking. Latency seems to be one of those things like antialiasing which enthusiasts will obsess over down to the subpixel or millisecond, but which most people will find that 'good enough' is good enough.

[MrGreen]

Hmm, that makes sense but if so why does Oculus now recommend vsync on? I suppose they feel the screen tearing is a bigger issue?

They always have recommended vsync on from the beginning - Palmer mentions it in pretty much any video where he talks about what you need for a solid VR experience.

It's Valve who are being contradictory in saying that vsync should be off in TF2.

And what do they know right!

I hate tearing but having my vision reflect my head movement only once every 16.6 ms sounds like a pretty good way to make me feel like crap. I think I'll take their word on this one.

Of course if your rig can't push more than 60 fps I guess that's a moot point.

I'd like to hear Palmer on this though.

[jayoh]

i guess in theory (i'm not a pro) that if you have enough overhead you won't get any tearing and you catch a couple extra frames from buffering up.

i don't know, but in UDK i'm seeing some tearing and i'm on a mission to crush it. it definitely hurts the experience.

[cybereality]

I personally think the experience is better with v-sync off. At least with the simple demos I've been testing with. The difference in latency is significant, while the tearing is hard to notice. Valve also recommends to turn v-sync off. Though of course, its very easy to test both ways, so I would encourage people to see for themselves.

[Endothermic]

Oh no.... you just went against your company... guess you didn't like working there

[V8Griff]

I've been running my Rift on an NVidia GTS 250 and that comfortably runs the Tuscany demo at 60Hz with V Sync enabled and the latency is very low. I'll try it without the V-Sync and report back if it alters the experience.

[Machinima]

In terms of latency, is triple buffer vsync any worse than double buffer?

[Mart]

Oh no.... you just went against your company... guess you didn't like working there

A great company is one that encourages employees to question the status quo.

[V8Griff]

I've tried the V-Sync on, off and adaptive and can report it makes no discernible difference on my set-up.

[EdZ]

I hate tearing but having my vision reflect my head movement only once every 16.6 ms sounds like a pretty good way to make me feel like crap.

With vsync off, you're still only pushing a new display update every 16.6ms. The difference is: with vsync, you know when every frame is going to arrive at the display, and you can iterate our simulation to the correct time, and intercept the correct head orientation late in the rendering pipeline. With vsync off, you have no idea when the frame you're rendering is actually going to be displayed. You'll end up with two or more parts of the screen showing the world at different simulation times, and only one of those updates will actually be the latest, lowest latency update.

Vsync off, the only latency gain you can possibly achieve by rendering above 60fps on a 60fps panel is during the readout-to-panel (i.e. the only frames newer than you'd get with vsync on are those that are completed after readout begins), and only ever over part of the screen. The greater the reduction in latency (i.e. the newer the frame), the smaller the area of the screen it actually applies to!

[pirsquared]

@V8Griff: If the difference is negligible I suppose vsync on is probably best unless the latency becomes unbearable. As for adaptive, its not any different from vsync unless your fps drops below 60!

[V8Griff]

@V8Griff: If the difference is negligible I suppose vsync on is probably best unless the latency becomes unbearable. As for adaptive, its not any different from vsync unless your fps drops below 60!

Yes so I've left it on. I guess the difference may show up in a more complex world however and I've not had time to test that yet.

[MrGreen]

I hate tearing but having my vision reflect my head movement only once every 16.6 ms sounds like a pretty good way to make me feel like crap.

With vsync off, you're still only pushing a new display update every 16.6ms. The difference is: with vsync, you know when every frame is going to arrive at the display, and you can iterate our simulation to the correct time, and intercept the correct head orientation late in the rendering pipeline. With vsync off, you have no idea when the frame you're rendering is actually going to be displayed. You'll end up with two or more parts of the screen showing the world at different simulation times, and only one of those updates will actually be the latest, lowest latency update.

Vsync off, the only latency gain you can possibly achieve by rendering above 60fps on a 60fps panel is during the readout-to-panel (i.e. the only frames newer than you'd get with vsync on are those that are completed after readout begins), and only ever over part of the screen. The greater the reduction in latency (i.e. the newer the frame), the smaller the area of the screen it actually applies to!

OK so it was very late...

And I'm probably a little dumb, too.

Why does mouse aiming in games feel much smoother with vsync off then? And why does Valve recommend to turn it off?

[LordJuanlo]

I play in 3 monitors (Eyefinity) with 3 graphics cards in Trifire. Vsync does not work properly with this configuration, so what I have done is limiting framerate. It's not the same than vsync but it works quite good. Some games have a built-in framerate limiter, but there are tools like MSI Afterburner or RadeonPro that allow to limit frames per second in any DirectX app. It does not look as good as vsync, but it removes a lot of tearing with zero input lag.

[Libertine]

Why triple buffering isn't a standard feature for DirectX is mind boggling to me. I'll take tearing over input lag any day of the week. Tearing makes the movement buttery smooth but the input lag makes games unplayable for me. (i don't own a Rift). I've been trying to use Vsync in Skyrim in 3D and the difference in movement is amazing. It makes panning around like swiveling a viewport to a real world around, but the input lag makes it almost unusable, even using D3DOverrider.

This is an excellent write up on how vsync and triple buffering work.
http://hardforum.com/showthread.php?t=928593

Have any of you Rift owners tried Direct 3D Overrider that comes with Rivatuner? I supposedly enables tripple buffering for DirectX games. The triple buffering in the Nvidia control panels supposedly is only for OpenGL.

[kt9mango]

By the way guys, if you are still getting issues with this then just make sure you have the Rift on as your preferred/main display and you shouldn't get any tearing.

Cheese

[shent1080]

I've got v-sync permenantly off and i'm getting no tearing whatsoever, not played a verio game yet but been through pretty much all the demo's plus HL2 and Portal. I don't have a souped up machine either, I5, 8gb ram, radeon 6850 (I know it sucks but it will do until I need to upgrade) and nothing, getting some motion blur but if you start turning your head in the rift as you do in real life (your eyes flick from one section to the next) then that's not too noticeable either. Can't wait for a better screen though, screen door is bearable......but could do with being reduced dramatically.