Any reason to NOT enable Adaptive Vsync by default?

I tend to use Vsync in games because tearing and juddering bothers me more than a little added latency. Is there any particular reason to NOT have Adaptive Vsync enabled by default in the Nvidia driver? I know what it does, just want to know if there are any obvious drawbacks that I've overlooked.

Variable refresh rate (Gsync/Freesync) isn't an option for me. I have a Freesync-capable monitor but only over HDMI, which only AMD cards support.

EDIT: What about fast sync?

 

As I get it, Fast Sync is for frame rates substantially higher the monitor`s refresh rate.

I used 60Hz monitor until last week. And I always switched Adaptive V-Sync ON. Now I have 144hz G-Sync compatible monitor and I am very glad.

 

I only recently upgraded my monitor, from 60Hz to 82Hz (actually 75Hz but overclocked). I foolishly asssumed that it supporting Freesync meant that it would support my Nvidia card through Gsync Compatible, but I didn't realise that Gsync Compatible doesn't work over HDMI like Freesync does. So can't use it unless I swap to AMD (not opposed to that in principle, just doesn't seem worth it).

 

well i have played a lot of games (mostly older) where it straight up didnt work few years ago,
so i used NVIDIAs own vsync or Fast Sync if framerate was very high
ofcourse that also didnt work sometimes, so all i was left with was good old regular vsync

 

Gsync only works via DP you should've known that. Swap the 2060 for rx5700 and enjoy freesync.

 

The obvious drawback of Adaptive Sync is that it demonstrates the disadvantages of both V-Sync off and V-Sync on depending on your framerate, to phrase it that way.

When framerate < refresh rate, V-Sync is off and you get tearing (and stutter).

When framerate >= refresh rate, V-Sync is on and you get high input latency.

The transition between the two can be pretty noticeable, particularly when you're at the boundary. Say you're at 58FPS, the game is tearing and there's a bit of stutter but it feels responsive. Then, suddenly, you're at 60FPS, no more tearing, the game feels much smoother (no partial torn frames), but there's suddenly much higher input latency.

One of the reasons to use Adaptive Sync is to avoid keeping V-Sync enabled when framerate < refresh rate, as this could cause severe stutter due to occasionally duplicated frames (missing scanout intervals every once in a while).

If your framerate swings too much, you'll be frequently entering and leaving each mode. This can be jarring.

If your framerate is mostly >= refresh rate, then once your framerate dips, Adaptive Sync will lessen the stuttering impact of that by disabling V-Sync at the expense of tearing. It will seem like a V-Sync on experience, most of the time.

None of the mentioned scenarios are ideal. Some people would rather increased responsiveness at all times (probably higher framerates too which decrease input latency further), and this means no V-Sync on whatsoever. Others would rather no tearing at all, and this means no V-Sync off whatsoever. Enabling a mode that swings between the two at will will satisfy neither category of people.

This is why variable refresh rate is such a great technology to have.

 

No need to be patronising. People make mistakes, an understandable one given that Freesync works over HDMI and 'Gsync Compatible' is nominally compatible with Freesync monitors. Not really worth a sideways change of graphics card for it.

Thanks for this. It seemed like the best of both worlds so felt it strange that it wasn't the default. Honestly, it'd be great if triple buffer vsync could be forced in D3D games like back in the day.

 

I would hardly call tearing the best of anything.

 

Triple buffering isn't that great. The framerate can now exceed the refresh rate, sure, but that means they are out of sync, with some frames arriving earlier and others arriving later (than usual). In other words, frametime variance means that you will still have jitter, a milder form of stutter, due to gametime and frametime not being exactly in sync.

There is no real solution to any of these issues other than variable refresh rate with quasi-instant scanout (for latency reduction). In other words, combined with extremely high refresh rates.

 

thats not how triple buffering works

 

Or lower! I used to play some games in 2160p60 with FastSync and ~45fps. Yes, there is judder but it's the better, lower latency version of tripple-buffer V-Sync (and can be "forced" on games where only double-buffer V-Sync would be available otherwise, regardless if you care about the lag of regular V-Sync or not).

 

I didn't know that.

 

You probably misunderstood what I meant. Also, you need to flush out your responses more than one-liners. Here's a more precise explanation of what I meant:

With triple buffering, the GPU now has two back buffers and one front buffer. The GPU's rendering is now decoupled from the refresh rate, as it can keep rendering to the back buffers. In VBLANK, the back buffer with the complete frame is chosen to be scanned out - the older frames are effectively "discarded" (they're no longer in any of the back buffers). Due to the decoupling of GPU rendering and refresh rate, the GPU will render a different amount of complete frames in each interval, each with a gametime related to when the frame started rendering. This means that every scanout, the gametime delta relative to the previously shown frame is different than the scanout interval and you get jitter. With double buffering, since GPU rendering is coupled to the refresh rate, gametime is aligned with the scanout interval and the deltas match as long as the framerate = refresh rate.

 

Problems with forced Adaptive Vsync for everything:

- If the user doesn't tolerate tearing and prefer reduced vsynced framerate

- If the game requires a locked framerate (by RTSS, Driver or whatever). It usually breaks adaptive vsync behaviour and produces constant tearing.

 

That's essentially what Nvidia's Fast Sync is for. D3D's implementation of "triple buffering" caused extra frames to build up in the render queue, which is bad for latency. However, using a FPS limiter and/or adjusting maximum pre-rendered frames was somewhat helpful to combat that problem.

 

There is an issue with adaptive vsync: When the application doesn't support triple buffering, there is a one-time stutter event when your frame rate drops below the refresh rate.

In the end, it's just one of those compromises that are all sh*t compared to VRR + LFC.

 

Honestly, I notice stuttering and/or tearing more than a little extra latency. I see the issue for competitive games and esports, but for me it was never enough latency to be a problem. All methods have their downsides, but this was the most tolerable.

I thought Fast Sync essentially requires twice the framerate?

 

Because vsync is just horrible on anything that isn't a vrr display? So many snowflakes holy cow. Crying about a little bit of tearing xD

How anyone can play with vsync without vrr is WAY beyong me. It is completely unplayable for me as the input lag is massive.

 

That’s why these things are toggle-able options, so users can set them as they like them. Some people are more bothered by input lag, others more bothered by tearing and judder.

“So many snowflakes holy cow. Crying about a little bit of input lag xD”

See?

 

You want vsync on as default giving everyone a worse experience if they don't know wtf those settings mean. Vsync off should be always the default. Period.