Double VSync

[ExtremeDude2]

I must of confused triple buffering input lag with framerate

Edit: actually I think the internet just lied to me (or you :p)

internet Wrote:This additional buffer gives the computer enough space to keep a buffer locked while it is being sent to the monitor (to avoid tearing) while also not preventing the software from drawing as fast as it possibly can (even with one locked buffer there are still two that the software can bounce back and forth between). The software draws back and forth between the two back buffers and (at best) once every refresh the front buffer is swapped for the back buffer containing the most recently completed fully rendered frame. This does take up some extra space in memory on the graphics card (about 15 to 25MB), but with modern graphics card dropping at least 512MB on board this extra space is no longer a real issue.

In other words, with triple buffering we get the same high actual performance and similar decreased input lag of a vsync disabled setup while achieving the visual quality and smoothness of leaving vsync enabled.

[NaturalViolence]

@xystus

Unless you can explain exactly what it does differently and how to measure any potential improvement I don't see how you're going to convince a dev to implement this. Your suggestion so far is to have dolphin cap vsync at 30 fps for 30 fps games. But it already does this so I'm not exactly sure what else you propose that they do.

@ED2

I guess technically it could reduce input lag if and only if it had a significant enough positive effect on framerate to offset the additional buffering.

[xystus]

(11-08-2013, 11:40 AM)NaturalViolence Wrote: @xystus

Unless you can explain exactly what it does differently and how to measure any potential improvement I don't see how you're going to convince a dev to implement this. Your suggestion so far is to have dolphin cap vsync at 30 fps for 30 fps games. But it already does this so I'm not exactly sure what else you propose that they do.

@ED2

I guess technically it could reduce input lag if and only if it had a significant enough positive effect on framerate to offset the additional buffering.

Well, I do notice a difference in performance - at stated earlier. So something's up for sure. I'm gonna check on the Radeon pro forum and get back to you.

[NaturalViolence]

Your performance as measured by dolphin/fraps is the same in both cases. You seem to be experiencing some kind of stuttering without double vsync as far as I can tell. But you can't tell us what's causing it, how to check for it, or what changes you propose be made to fix it. That is the issue.

Have you tried using dolphins framelimiter set to a 30 fps limit in these games and comparing against that?

I've seen users resolve stuttering issues this way which makes me think it might be an issue with dolphin using 29.976 fps instead of 30.0 fps as the limit, or vice versa. It could just be a case of NTSCM standards not fully agreeing with the way the real hardware does things.

[xystus]

japamd;4697116 Wrote:Also know as half-refresh, double vsync instructs the driver to wait for 2 vertical retrace cycles for each frame causing a 60Hz to display 30 frames per second. It's not the same and normal vsync + frame rate cap @ 30 FPS should result in less input lag than waiting for 2 vertical retrace cycles.

[NaturalViolence]

I've read that in the docs. But how is that any different from vsync + 30 fps cap which should also force it to draw one frame every two retrace cycles? And why would it effect stuttering?

[Sir Chief]

I didn't even know double Vsync existed...