How does adaptive refresh rate technology works on smartphones?

[MS-DOS]

Im looking to buy a s23 or s24 and I saw that they support 120hz, but the refresh rate is dynamic and changes depending on what you are doing. Some dude here said YouTube was running at 60hz as well as games. What's the idea? Why would you want an high refresh rate if videos and games are not running at 120hz at all times? 120hz only works for scrolling throught things on the menus? This makes no sense.

 

s23 can go as low as 10hz in steps of 120, 96, 60, 48, 30, 24 and 10 Hz.

s24 can go from 120hz to 1hz in steps of 1hz.

 

I just don't get it. What's the point? you save battery, but ruin the point of having 120hz, which is to have your eyes resting better since the screen updates faster, and not only when you are moving it with your finger. Im also not understanding how the screen isn't going to cause strobbing thus discomfort to look at if it runs at such low hz's. This is just a weird thing unless im missing something here.

 

Is there some way to force 120hz locked at all times at least when you run certain apps? I could lock videogames as well as video apps like YouTube or VR video apps. I will have enough battery time I suppose, since I use the phone 1 hour a day and rarely I would use it more. I just want a smooth experience and not have a headache and higher refresh rates helps a lot.

 

If someone knows exactly how this works, I hope my post makes sense and would like what you think.

[SImoHayha]

you can use a 3rd party app called Galaxy MaxHZ. Which is on github you sideload the app. I use it to control my refresh rate for my phone to save more power.   You can use it for your usage case I think you can force it to 120hz. 

you also have to pay for additional features but its only 3$~ approximate but you can test it for free and a few features for free it works pretty well. So you can try it and see if it works. 

[Kilrah]

1 hour ago, MS-DOS said:

which is to have your eyes resting better since the screen updates faster, and not only when you are moving it with your finger. Im also not understanding how the screen isn't going to cause strobbing thus discomfort to look at if it runs at such low hz's.

It's not a CRT, it doesn't depend on new incoming pictures to put light out, refresh changes nothing for your eyes. The screen just holds the last picture until a new one is received, and the phone simply doesn't send new ones at full blast when there's no reason to because nothing changed.

 

Videos on youtube aren't 120Hz, so no point. Games rarely can run at 120Hz on phones, not enough power. If one can it'll most likely make use of it.

[jaslion]

1 hour ago, MS-DOS said:

said YouTube was running at 60hz as well as games. What's the idea? Why would you want an high refresh

Because yt max fps is 60 and most mobile games wont do past 60 hard locked. As anothrt said you can force it on but well that severly eats battery life.

 

 

[manikyath]

basicly, assume it sends out a new frame when there is one to display. scrolling takes very little compute so it can go very fast, but youtube is either 30 or 60fps, and high refresh rate gaming on mobile is a huge drain on available resources... so it doesnt make much sense.

 

it's a way of overal making the ui feel very smooth, while limiting resource usage when it's not necessary. you dont even need 30fps to read a static webpage, so why crank out frames there anyways?

[MS-DOS]

On 9/13/2024 at 9:11 AM, Kilrah said:

It's not a CRT, it doesn't depend on new incoming pictures to put light out, refresh changes nothing for your eyes. The screen just holds the last picture until a new one is received, and the phone simply doesn't send new ones at full blast when there's no reason to because nothing changed.

 

Videos on youtube aren't 120Hz, so no point. Games rarely can run at 120Hz on phones, not enough power. If one can it'll most likely make use of it.

I recently understood the differene between PWM and refresh rate. I thought it was the same because I noticed the lower flicker rate on lower refresh rate with CRT. But this is confusing since I still noticed it post CRT (I have had Samsung 2233rz and ViewSonic XG2401 since I left CRT, and I notice it if I lower the refresh rate to 60hz and then go back to 144hz)

[MS-DOS]

On 9/13/2024 at 12:29 PM, manikyath said:

basicly, assume it sends out a new frame when there is one to display. scrolling takes very little compute so it can go very fast, but youtube is either 30 or 60fps, and high refresh rate gaming on mobile is a huge drain on available resources... so it doesnt make much sense.

 

it's a way of overal making the ui feel very smooth, while limiting resource usage when it's not necessary. you dont even need 30fps to read a static webpage, so why crank out frames there anyways?

Because like I said above, I was confusing the PWM rate with refresh rate.

As far as dynamic refresh rate, is it noticeable when it switches between 10-24-48 etc? i guess there is a delay in everything.

Has anyone tried the S23 or S24?

I saw that S23 has 240hz PWM and S24 480hz so perhaps this is a deciding factor. Here you can see the difference:

 

 

[manikyath]

37 minutes ago, MS-DOS said:

is it noticeable when it switches between 10-24-48 etc? i guess there is a delay in everything.

the idea of dynamic refresh rate is literally that it only refreshes if there is content to display. so instead of your 120hz display showing every frame of a 30fps video four times, it just updates the screen slower, to match the speed of frames coming in.

[Lurking]

46 minutes ago, MS-DOS said:

Because like I said above, I was confusing the PWM rate with refresh rate.

As far as dynamic refresh rate, is it noticeable when it switches between 10-24-48 etc? i guess there is a delay in everything.

Has anyone tried the S23 or S24?

I saw that S23 has 240hz PWM and S24 480hz so perhaps this is a deciding factor. Here you can see the difference:

I don't know those phones. But adaptive refresh rate should NOT be noticeable. 

 

As soon as you touch the screen to scroll, the phone already "knows" it needs to increase refresh-rate. 

 

For my phone I can display the refresh rate (developer options). It literally jumps to 120Hz the nano-second I do anything. Even putting the phone on the wireless cradle increases to 120Hz for a second just because the phone anticipates some action. It also drops back to the low rate once the screen isn't changing anymore or doesn't have quick changes (like just YT). 

 

FWIW, I only can tell the difference scrolling with 60Hz (when I manually set it to slow and not adaptive) and 120Hz if I scroll really fast and pay attention.