Is FreeSync/GSync even useful in very high refresh rate monitors (e.g. 240+ Hz)?

[TechDeck97]

Recently, I was doing some testing of how noticeable tearing is on my 144 Hz monitor in three different refresh rate cycles; 60, 120, and 144 Hz.

When running the games at 60 FPS, on the 60 Hz refresh rate the tearing was quite noticeable, however, the more I went up in range, the harder it was to notice.

At 120, and 144 Hz, I could notice tearing only if I specifically direct my attention to it, and ignored anything else going on in-game.

With the 240+ Hz refresh rate displays being available on the market nowadays, this made me wonder just how useful the Sync technologies are.

I mean weren't the FreeSync/GSync technologies created to eliminate tearing in the first place, by dynamically synchronizing the display's refresh rate to that of the GPU's frame rate output?

So if your display refreshes a high amount of times per second that the tearing would be unnoticeable to the human eye, wouldn't that make FreeSync/GSync technologies obsolete, or useless?

I don't follow the developments of Sync technologies, so I apologize for my ignorance on this topic. This thought randomly popped into my head, so I decided to do some experiments with my own 144 Hz monitor just to see how noticeable the tearing was at those intervals, which kind of led me to the conclusion that unless you directly focus your attention on it, you probably wouldn't notice any tearing at all, because of course, your focus would be on the game itself, not the image synchronization.

Also, slightly off-topic question; What is the minimum amount of time our brain can register the image we see?

The only thing on this topic I've seen was this: https://news.mit.edu/2014/in-the-blink-of-an-eye-0116

However, a team of neuroscientists from MIT has found that the human brain can process entire images that the eye sees for as little as 13 milliseconds — the first evidence of such rapid processing speed. That speed is far faster than the 100 milliseconds suggested by previous studies.

And here we already have displays that refresh images every:
6.94ms (144 Hz)
4.167ms (240 Hz)
2.78ms (360 Hz)

So, if we achieve a refresh rate that refreshes the screen below the human brain's possible image registration time, wouldn't it be pointless to go higher than that as far as displays are concerned?

[Chief Blur Buster]

So, if we achieve a refresh rate that refreshes the screen below the human brain's possible image registration time, wouldn't it be pointless to go higher than that as far as displays are concerned?

It's not as simple as that.

There are many variables:

- Everybody sees differently / picky about different things.
Whether you're bothered by it, or just "notice but don't care", or truly cannot see

- You notice differently for different eye-gaze and different motion-material.
(A) Stationary eyeballs, stationary images on screen
(B) Stationary eyeballs, Moving objects on screen
(C) Moving eyeballs, stationary objects on screen
(D) Moving eyeballs, Moving images on screen
Examples:
www.testufo.com/mousearrow
www.testufo.com/eyetracking
www.blurbusters.com/stroboscopics
www.blurbusters.com/1000hz-journey

- Motion blur (caused by slow displays or low refresh rates / low frame rates) can hide flaws by sync technologies.
That's why turning on strobing can make tearing more visible to some people

- Larger geometric upgrades are necessary for diminishing curve of returns.
That's why 240Hz vs 1000Hz is more human visible even to your grandma than 144Hz vs 240Hz - see this post)

- Bottlenecks in display ability to handle the Hz
240Hz vs 360Hz can be diminished to an even tinier difference (e.g. 1.1x difference) instead of its number-related 1.5x difference because of other factors such as slow LCD GtG and jitter. That's why 240fps 240Hz on an OLED is clearer than 360fps 360Hz on an IPS LCD, too.

- Higher resolutions amplify refresh rate limitations
8K means even 8000 pixels/sec can still have 8 pixels of motion blur at 1000fps 1000Hz.

- Etc

There's a lot more reading available at www.blurbusters.com/area51 -- I am incited in over 25 research papers now;

[jorimt]

With the 240+ Hz refresh rate displays being available on the market nowadays, this made me wonder just how useful the Sync technologies are.

I mean weren't the FreeSync/GSync technologies created to eliminate tearing in the first place, by dynamically synchronizing the display's refresh rate to that of the GPU's frame rate output?

So if your display refreshes a high amount of times per second that the tearing would be unnoticeable to the human eye, wouldn't that make FreeSync/GSync technologies obsolete, or useless?

Ultimately, VRR is merely a stopgap to ultra high refresh rates where tearing will be all but imperceivable, regardless of framerate, but we're not quite there yet; I can still easily discern tearing on my 240Hz monitor, for instance, it's just less noticeable than it is at lower refresh rates.

Once we hit ~1000Hz+, however, syncing methods (including VRR), will be effectively obsolete, but in the meantime we "need" them for tear-free operation, similar to what strobing does for motion persistence at currently achievable frame + refresh rate ratios.

[TechDeck97]

It's not as simple as that.

There are many variables:

- Everybody sees differently / picky about different things.
Whether you're bothered by it, or just "notice but don't care", or truly cannot see

- You notice differently for different eye-gaze and different motion-material.
(A) Stationary eyeballs, stationary images on screen
(B) Stationary eyeballs, Moving objects on screen
(C) Moving eyeballs, stationary objects on screen
(D) Moving eyeballs, Moving images on screen
Examples:
www.testufo.com/mousearrow
www.testufo.com/eyetracking
www.blurbusters.com/stroboscopics
www.blurbusters.com/1000hz-journey

- Motion blur (caused by slow displays or low refresh rates / low frame rates) can hide flaws by sync technologies.
That's why turning on strobing can make tearing more visible to some people

- Larger geometric upgrades are necessary for diminishing curve of returns.
That's why 240Hz vs 1000Hz is more human visible even to your grandma than 144Hz vs 240Hz - see this post)

- Bottlenecks in display ability to handle the Hz
240Hz vs 360Hz can be diminished to an even tinier difference (e.g. 1.1x difference) instead of its number-related 1.5x difference because of other factors such as slow LCD GtG and jitter. That's why 240fps 240Hz on an OLED is clearer than 360fps 360Hz on an IPS LCD, too.

- Higher resolutions amplify refresh rate limitations
8K means even 8000 pixels/sec can still have 8 pixels of motion blur at 1000fps 1000Hz.

- Etc

There's a lot more reading available at www.blurbusters.com/area51 -- I am incited in over 25 research papers now;

That's a lot of useful information, thank you for that Chief

Also, those stationary/motion tests were really interesting, glad you guys made them.

Ultimately, VRR is merely a stopgap to ultra high refresh rates where tearing will be all but imperceivable, regardless of framerate, but we're not quite there yet; I can still easily discern tearing on my 240Hz monitor, for instance, it's just less noticeable than it is at lower refresh rates.

Once we hit ~1000Hz+, however, syncing methods (including VRR), will be effectively obsolete, but in the meantime we "need" them for tear-free operation, similar to what strobing does for motion persistence at currently achievable frame + refresh rate ratios.

Oh, wow, this makes me wonder just when will we be able to reach displays with a 1000+Hz refresh rate, and the tests performed on them. I'll definitely be looking forward to it

Thanks again for the replies from both of you. Glad I learned something from this little experiment