Does low response time feel better than high refresh rate?

[Hi P]

Let's say that we have the following monitors:

• A: 75 Hz, 1 - 2 ms
• B: 120 Hz, 10 - 12 ms

 

Would monitor A look and feel better than monitor B due to its lower response time?

[johnt]

I'm pretty sure there is an inverse relationship between refresh rate and response. A higher refresh rate will always correlate to a lower response time.

 

response time = 1 / refresh rate

 

I am answering this way because you are talking about monitors. There could be additional system latency that could add to your overall response time, but I mean it's all traveling at the speed of light... in practice, the higher the frame rates, the better the experience. Although there is diminishing marginal returns (where more frames doesn't matter as much), but who knows where that limit is. A lot of reviews say that 144 Hz is the sweet spot, but there's many out there who can benefit from higher refresh rates.

[heimdali]

What do you mean by "response time"?  If you compute a value as 1 / (120Hz/sec) the result is 0.008333333Hz sec.  So you'd have a "response time" of 0.008333333Hz sec, whatever that means.  How would this value be related to how long it takes before you can see a change on the display, if that matters?  The display can take as long as it wants before it shows something as long as it displays 120 images per second because that's what it's rated for.  Nobody says what the images it displays have to look or feel like.

 

Do you get images that "feel better" when the "response time" is 0.013333333Hz sec instead of 0.008333333Hz sec?

 

[Glenwing]

59 minutes ago, johnt said:

I'm pretty sure there is an inverse relationship between refresh rate and response. A higher refresh rate will always correlate to a lower response time.

 

response time = 1 / refresh rate

 

22 minutes ago, heimdali said:

What do you mean by "response time"?  If you compute a value as 1 / (120Hz/sec) the result is 0.008333333Hz sec.  So you'd have a "response time" of 0.008333333Hz sec, whatever that means.

 

That's frame time, not response time.

[e22big]

Low response time means you'll see less artefacts in moving animations (like ghosting or smearing)

 

High refresh rate means you'll 'see' a smoother fast animation, and often accompanied by positive effects like lower input lag and lower latency which responsible for your 'feeling' that everything became snappier and more responsive (when you can also render your animation at higher fps, of course.) 

*Nvidia DLSS 3.0 is an exception this rule. You get more fps but input lag and latency also increased not decreased, which resulted in only the visual effect of a 'smoother animation' but not the 'snappier feeling' you typically want in competitive gaming 

 

So low response time doesn't make you 'feel better', it give you a more precise and pretty animation but you need higher refresh rates or other hardware property (OLED, Nvidia Reflex etc.) to 'feel better'. 

[heimdali]

1 hour ago, Glenwing said:

 

That's frame time, not response time.

Ok, and what about the units?  It's Hz times seconds, and I totally suck at math and don't understand what that could mean.  Wikipedia says "The hertz is equivalent to one cycle per second." (https://en.wikipedia.org/wiki/Hertz)

 

That's 1 cycle / 1 second, and 0.008333333Hz * sec means 0.008333333 cycle / second * second and your response time (i. e. your cycle) is 0.008333333 seconds^2.  What is that supposed to mean?

 

(The reason why I suck at math is that I understand stuff by removing abstractions.  When you do that with math, nothing is left.  That's why you need to explain it to me.  What is 0.008333333s^2??  That can't be a "frame time", can it?)

 

[Glenwing]

6 minutes ago, heimdali said:

Ok, and what about the units?  It's Hz times seconds, and I totally suck at math and don't understand what that could mean.  Wikipedia says "The hertz is equivalent to one cycle per second." (https://en.wikipedia.org/wiki/Hertz)

 

That's 1 cycle / 1 second, and 0.008333333Hz * sec means 0.008333333 cycle / second * second and your response time (i. e. your cycle) is 0.008333333 seconds^2.  What is that supposed to mean?

 

(The reason why I suck at math is that I understand stuff by removing abstractions.  When you do that with math, nothing is left.  That's why you need to explain it to me.  What is 0.008333333s^2??  That can't be a "frame time", can it?)

 

Frame time is just the duration of each refresh cycle, which is just the reciprocal of refresh frequency. So if the refresh frequency is 100 Hz, the frame time is 10 ms. Each frame is displayed for 10 ms, and 100 of them at 10 ms each makes 1 second.

 

Response time is how long it takes for the pixels to change to the new color. This is independent of how long the frame lasts.

[heimdali]

57 minutes ago, e22big said:

Low response time means you'll see less artefacts in moving animations (like ghosting or smearing)

What does that have to do with the refresh rate?

57 minutes ago, e22big said:

High refresh rate means you'll 'see' a smoother fast animation, and often accompanied by positive effects like lower input lag and lower latency which responsible for your 'feeling' that everything became snappier and more responsive (when you can also render your animation at higher fps, of course.) 

Well, if the "response time" is high enough, what will you see?  Probably not a "smoother animation" but more artifacts and you can't exactly tell what you're looking at.  So when you have a TV which manages a "response time" of 11ms, you can't exactly tell what you're looking at when you have it at 120Hz because you get a new frame every 8.33ms.

 

So the smoother (assuming that the animation is actually being done in smaller steps) the animation is, and the less latency you have, the less you can tell what you're looking at.  How does that make you feel better, if it does?

57 minutes ago, e22big said:

*Nvidia DLSS 3.0 is an exception this rule. You get more fps but input lag and latency also increased not decreased, which resulted in only the visual effect of a 'smoother animation' but not the 'snappier feeling' you typically want in competitive gaming 

So you can finally see what you're looking at?

57 minutes ago, e22big said:

So low response time doesn't make you 'feel better', it give you a more precise and pretty animation but you need higher refresh rates or other hardware property (OLED, Nvidia Reflex etc.) to 'feel better'. 

You mean hardware that can display the animation fast enough?  The OP is asking the wrong question then.

[heimdali]

9 minutes ago, Glenwing said:

Frame time is just the duration of each refresh cycle, which is just the reciprocal of refresh frequency. So if the refresh frequency is 100 Hz, the frame time is 10 ms. Each frame is displayed for 10 ms, and 100 of them at 10 ms each makes 1 second.

 

Response time is how long it takes for the pixels to change to the new color. This is independent of how long the frame lasts.

Ok but when I carry the units through the equation, I get square seconds.  Did I do it wrong or how am I supposed to imagine square seconds?  How long is a square second?

[Glenwing]

39 minutes ago, heimdali said:

Ok but when I carry the units through the equation, I get square seconds.  Did I do it wrong or how am I supposed to imagine square seconds?  How long is a square second?

Not sure what you mean or where you're getting square seconds from. The refresh frequency is in hertz, or 1/seconds. The frame time is the reciprocal of the refresh frequency, so the units are in seconds.

[johnt]

7 minutes ago, Glenwing said:

Not sure what you mean or where you're getting square seconds from.

wtf are they teaching kids these days 

[heimdali]

26 minutes ago, Glenwing said:

Not sure what you mean or where you're getting square seconds from. The refresh frequency is in hertz, or 1/seconds. The frame time is the reciprocal of the refresh frequency, so the units are in seconds.

That's from the equation ... I think I did it wrong by ignoring that it's not 120Hz/s.  120Hz/s is bullshit because Hz stands for cycle/s already and it's just 120Hz.

 

[e22big]

1 hour ago, heimdali said:

What does that have to do with the refresh rate?

Well, if the "response time" is high enough, what will you see?  Probably not a "smoother animation" but more artifacts and you can't exactly tell what you're looking at.  So when you have a TV which manages a "response time" of 11ms, you can't exactly tell what you're looking at when you have it at 120Hz because you get a new frame every 8.33ms.

 

So the smoother (assuming that the animation is actually being done in smaller steps) the animation is, and the less latency you have, the less you can tell what you're looking at.  How does that make you feel better, if it does?

So you can finally see what you're looking at?

You mean hardware that can display the animation fast enough?  The OP is asking the wrong question then.

It's late so let me be quick about it before going to sleep.

 

To sum it all up, let me answer this question 'What does that have to do with the refresh rate?'

 

TL;DR it has nothing to do with it, generally a monitor may have better response at a higher refresh rate but that wasn't always the case (which is typical when a monitor is forced to run at a higher refresh rate despite not really well suite for it, like when overclocking the display)

 

Like Glen had said, a response time is the time in which the monitor 'response' to the change of colour - not user input. A faster response time means it can change from one colour to another quickly, which result in a more seamless and accurate animation. 

 

TL;DR of the TL;DR it produces less ghosting and smearing, which can happen when there's a moving animation on the display regardless of your input. If a monitor has poor response time, you'll see a trail of dark or light colour around the moving objects regardless of whether it's game or video. 

 

Refresh rate help create a smoother animation - more spesifically, it makes fast animation looks more realistic and it correlate directly with improved latency and input lag. It can make your system feel more responsive because of the lower input lag (which is self-explanatory) but it will not and could not help with your monitor response time (except when the monitor response time is optimum at a higher refresh range)

 

Take Samsung QN90B 43 inch TV for example. This monitor has a fast 144 hz refresh rate but it doesn't has the greatest response time and it has the best response time at 120 hz not 144 hz refresh range 

 

This mean, when running at 144hz, you'll still see a smoother animation due to higher refresh rate but also most likely black smearing around a dark object because the monitor has now run well over the range it was optimised for and started to produce more artefacts despite still yielding all the benefit of a higer refresh rate display.

 

Hope that helps

[heimdali]

27 minutes ago, johnt said:

wtf are they teaching kids these days 

The problem is what they're /not/ teaching, like how to imagine what a square second is.  What do you think might happen if they gave the kids the idea that they could imagine something?  It's incredibly dangerous to teach that.  Before you know it, they'll even ask questions ...

 

[johnt]

4 minutes ago, heimdali said:

The problem is what they're /not/ teaching, like how to imagine what a square second is.  What do you think might happen if they gave the kids the idea that they could imagine something?  It's incredibly dangerous to teach that.  Before you know it, they'll even ask questions ...

 

Squared seconds has its place in physics (acceleration for something logical, and then weight/energy and electricity get quite abstract).

 

cycles = Hz = 1 / s

 

time = 1 / Hz = 1 / (1/s) = s

 

No square seconds between time and cycles.

[heimdali]

1 minute ago, johnt said:

Squared seconds has its place in physics (acceleration for something logical, and then weight/energy and electricity get quite abstract).

Yes, and I never understood what a square second is supposed to be or how to imagine one or how long one takes.  Nobody ever taught me that and I can't figure it out as long as I don't know what they mean by a square second.  See the problem?

 

[johnt]

7 minutes ago, heimdali said:

Yes, and I never understood what a square second is supposed to be or how to imagine one or how long one takes.  Nobody ever taught me that and I can't figure it out as long as I don't know what they mean by a square second.  See the problem?

 

Fair. I don't think a squared second is directly logical anyway.

 

Consider acceleration, for example. The SI units are typically meters per seconds squared. But since it is a change in speed, you can think about the units as how fast something is changing speed, or the rate the speed is changing. Like "meters/second PER second." This breaks down to meters per squared seconds when you factor and group the units, but they do this to make things look pretty and consistent. But really it doesn't mean anything.

 

You can also get inconsistent units that make more sense. Like in the US, you could say the acceleration is "2 MPH per second." This could also be written as "2 miles per hour-seconds." Which is the same as square seconds in concept.

 

Totally tangent  

[BuzzingBee]

4 hours ago, Hi P said:

Let's say that we have the following monitors:

• A: 75 Hz, 1 - 2 ms
• B: 120 Hz, 10 - 12 ms

 

Would monitor A look and feel better than monitor B due to its lower response time?

These examples are kind of realistic I experienced: Monitor A would be OLED capped at 75 FPS, and monitor B would be VA (although a bit better than 10ms).

 

So which one look better?

Monitor A would definitely "look" better because with 75hz & 1ms response time it would roughly take 12ms of still image and 1ms transition to another image.

Monitor B would not able to produce clear image because response time is more than monitor A, in fact its too slow it would be slower than its refresh cycle, so it would end up overlapping and has ghosting effect. 

 

But despite all of this, monitor B still "feels" better, although I can't explain this scientifically, the more higher refresh rate the more we perceive smoother motion. Also it can give less input delay as there's more updates per second, hope that makes sense. No one wants to use desktop at 30Hz even if it's OLED, it's slower, laggy and jittery... 

[heimdali]

8 hours ago, johnt said:

Fair. I don't think a squared second is directly logical anyway.

 

Consider acceleration, for example. The SI units are typically meters per seconds squared. But since it is a change in speed, you can think about the units as how fast something is changing speed, or the rate the speed is changing. Like "meters/second PER second." This breaks down to meters per squared seconds when you factor and group the units, but they do this to make things look pretty and consistent. But really it doesn't mean anything.

 

You can also get inconsistent units that make more sense. Like in the US, you could say the acceleration is "2 MPH per second." This could also be written as "2 miles per hour-seconds." Which is the same as square seconds in concept.

 

Totally tangent  

That's a really good explanation, thank you   It still doesn't make sense, though, and why do they come with things like square seconds when they don't mean anything.  It would be much easier if they were to say how fast or slow something goes faster or slower.

 

It gets funny when something doesn't go faster or slower but does so faster or slower.  What happens then, and what kind of condition is that?  I reckon monitors can do that, but other than that?

 

[heimdali]

7 hours ago, BuzzingBee said:

No one wants to use desktop at 30Hz even if it's OLED, it's slower, laggy and jittery... 

That's kinda true ... I have had that for a while because I couldn't find a display port cable at first that would do 4k@60Hz and got only 4k@30Hz.  IIRC, I had to return two of them before I got one that worked.  30Hz is usable (because LCDs don't flicker like CRTs) and not jittery, yet it's slow and not so much fun.

 

Having that said, you guys just convinced me that when I get a new display, I'll go for at least 120Hz not because I would think I'd need one but it might be like the difference between 30 and 60Hz, and that's something I would definitely want.

[Doobeedoo]

Really first 75Hz with that ms is not even possible how slow LCD is, modern fastest and much higher Hz monitors barely can reach near that. 

That 120Hz second example would be blurry trash outright and not even actual 120Hz in the end. We've seen many early monitors pushing 120Hz+ but in reality they could barely be fast enough for 90Hz.

Advertised ms need to be taken with * though. 

[Hi P]

On 11/9/2022 at 8:14 AM, Doobeedoo said:

Really first 75Hz with that ms is not even possible how slow LCD is.

But what about OLED? I thought it was possible as mentioned by @BuzzingBee

 

On 11/9/2022 at 8:14 AM, Doobeedoo said:

That 120Hz second example would be blurry trash outright and not even actual 120Hz in the end.

This is very interesting, something that I will keep in mind

[Doobeedoo]

14 minutes ago, Hi P said:

But what about OLED? I thought it was possible as mentioned by @BuzzingBee

 

This is very interesting, something that I will keep in mind

Yeah OLED is different, it's much faster and can deliver proper ms for each frame. So no ghosting like with LCD even with good overdrive and higher Hz.

Still OLED with lower refresh rate on motion can seem stuttery since each frame is more clear and transition between them will look more apparent. So say higher refresh rate LCD can feel more smooth vs lower refresh OLED because well actually it does show more frames, even though they are blurry. In that context it would be do you want clear frames but less, or blurry but more. Obviously OLED is way better vs LCD both using same Hz no doubt. Strobing is something also a good to have for both.