Someone explain FPS to me

[Kerbart]

I grew up with slow computers. Flightsims running at 15 FPS if you pushed your sliders too hard — and around 12 FPS landing becomes an issue.

So it's nice to get somewhere close to monitor refresh rates — in my book, 20 FPS is actually fine (I'm blessed in a way). Now, I get that you'd want 25 FPS or 30 FPS - the refresh rate of an old school monitor. There's a reason movie theaters, TV's and CRT's had refresh rates like that, because our eyeballs don't refresh any faster.

So, explain to me like I'm 5, because I can't figure this out: why is it so important to have refresh rates of 60 FPS to 120 FPS?

I'm not saying there's something wrong with those who want  it—it's expensive to get there, so I'm sure there's a good reason. I just want to know what I'm missing out on if I don't run at 120 FPS.

[kerbiloid]

A guess.

Cuz when you are iPhoning the screen, it's blinking, while consoles don't allow to install a video recording soft.

Thus, you are trying to show to your friends  what a cool player you are, and they are watching a blinking video and think instead that you are a poor loser without iPhone.

So, the higher is frequency, the smoother is film, the stronger you look.

[Nuke]

30fps* has always been held as the magical fps. but that may be because of the way a film projector works. it doesn't display the frame for the full interval, it only opens the shutter when the frame is in the correct position.  for the rest of the frame interval there is only black. when we moved to video systems, a lot of shows started to have what has been called "the soap opera effect" (this effect is reduced on shows that were recorded on film and then transfered to video, compare st:tng to babylon5 is a good example). tvs, at least their crt anscestors, used phosphors to allow the frame to persist. so the frame was drawn and would slowly fade over time. you also interleaved 2 fields of alternating scanlines which swaps each frame.  you are still blinking the frames, but for longer period of time. 

of course various flat panel technologies all changed that, and still do to this day. a frame can now persist for the whole interval with little or no blanking. persisting a frame like this makes the data get old the longer it lives on screen. gaming has also introduced a need to reduce the time it takes to scan out a frame. while you could reduce the time between the render call and the frame appearing on screen, you could simply let the frame persist. but if you can do that you have time to render more frames, and so thats what we do. this fills up the interval with new data, even if you are integrating your physics at a slower rate (interpolation tricks are used in this case). the whole point is to reduce the amount of time it takes to react to the game. vr has taken this to an extreme by racing the beam where a pixel is put on screen before the frame (or even scanline) has even finished rendering. 

human brain does not work with a fixed clock like your monitor does. i think the eye reacts with changes in stimuli as they happen rather than scan everything always. so when your brain gets around noticing a pixel changing, it could be at any point in the render process, a new pixel, one thats been up a few milliseconds. resolution across the eye isnt even consistent, most of your res and sensitivity is in the middle of the visual field. so i figure a good portion of the pixels that actually render never even make it to your brain. early film and tv, with its blinking output, kind of forced your brain to refresh by blinking, and i think that may be why film is considered "magical".

ultimately framerates are used as useless marketing data on various technologies. the thing that really matters is the latency. how much you can live with really depends on what you are doing. vr needs to have very low latency to reduce motion sickness. esports also benefit to help player's reaction times. most other games on the other hand, such as casual games, it really doesn't matter. it does very little for video. when i buy a screen, i usually go for size, then resolution, then framerate. now doing 4k at 144hz, and i doubt it has really improved games, or video at all over the 60hz display i was running. 

 

*24 fps is actually the magic fps for cinema. idk why i said 30. 

Edited April 9, 2023 by Nuke

[JoeSchmuckatelli]

On 2/20/2023 at 12:00 PM, Kerbart said:

I grew up with slow computers. Flightsims running at 15 FPS if you pushed your sliders too hard — and around 12 FPS landing becomes an issue.

So it's nice to get somewhere close to monitor refresh rates — in my book, 20 FPS is actually fine (I'm blessed in a way). Now, I get that you'd want 25 FPS or 30 FPS - the refresh rate of an old school monitor. There's a reason movie theaters, TV's and CRT's had refresh rates like that, because our eyeballs don't refresh any faster.

So, explain to me like I'm 5, because I can't figure this out: why is it so important to have refresh rates of 60 FPS to 120 FPS?

I'm not saying there's something wrong with those who want  it—it's expensive to get there, so I'm sure there's a good reason. I just want to know what I'm missing out on if I don't run at 120 FPS.

It generally depends on what you are playing and how fast the image is changing, more than anything. 

Relatively sedate movement on the screen, like you see in flight Sims is playable at 20 FPS okay at 30 and good at 60.  Play (or try to) play a FPS (first person shooter) with those numbers and at 20 its not only bad, but you can't do anything. At 30 you are getting killed by the other guys in most situations because they have a higher chance of seeing you first, and at 60 you can play fine - but it can still feel stuttery and people with faster refresh still have a slight advantage (above 60 is about being competitive - and also relies on your ability to process info faster than average (which, 50 % of the population do. 

Higher refresh rate can also fight simulation sickness - that feeling of nausea you can get from stutters and weird movements in your field of view (think car sick).  I almost never have this but with 20FPS on the runway at the KSC and the warp turned up enough for me to watch the sky go from midnight to past sunrise I got a whiff of nausea. 

Now when I first started playing MSFS 20 FPS let me play the game but it wasn't really fun.  Getting it up to the 60s allows for greater immersion. 

The other thing really is about personal perception - and I'm talking about ability rather than preference from reading reviews.  I'm one of those guys who can see the individual pixels on a 24 inch 1080p screen while sitting 3 feet away.  It used to bug me.  It's also one of the reasons I stepped up to 4k - which increases my pixel density at the same distance.  This makes scenes look more natural and not grainy. 

I can also see the difference between a FPS running 60 frames and when I get it above 120 (or rather, I stop detecting the refresh when the hardware can push frames fast enough).  It's subtle but noticeable and a QOL issue.  

Oh... And watch this on a full screen with high quality.  You can see as I rotate the camera around the craft and look at the ground that it doesn't have a natural movement feel.  There are stutters. 

I can play KSP2 with 20 fps but it is an effort of will to ignore the performance 

 

 

[Kerbart]

2 hours ago, JoeSchmuckatelli said:

[...]

Oh... And watch this on a full screen with high quality.  You can see as I rotate the camera around the craft and look at the ground that it doesn't have a natural movement feel.  There are stutters. 

I can play KSP2 with 20 fps but it is an effort of will to ignore the performance [YT}

Thank you - that puts it in perspective for me.

[ColKlonk2]

Old monitors, CRT types had their refresh rates (FPS) locked/synced to the mains electricity supply which was either 50 or 60 hertz depending on your country.

With the advent of LED, now OLED 'digital' monitors the FPS rates became independent of the mains supply,  and variable up to a maximum of what made sense for the particular application in use, limited again by the monitor/screen hardware.

The more 'powerful' your graphics card that drives your screen, the less time it takes to render a scene frame (which is applied to the screen), resulting in a potential higher FPS rate.

[Nuke]

3 hours ago, ColKlonk2 said:

Old monitors, CRT types had their refresh rates (FPS) locked/synced to the mains electricity supply which was either 50 or 60 hertz depending on your country.

With the advent of LED, now OLED 'digital' monitors the FPS rates became independent of the mains supply,  and variable up to a maximum of what made sense for the particular application in use, limited again by the monitor/screen hardware.

The more 'powerful' your graphics card that drives your screen, the less time it takes to render a scene frame (which is applied to the screen), resulting in a potential higher FPS rate.

initially perhaps, but having used several crt monitors a wide array of refresh rates and resolutions were possible. clocks have been derived from crystal oscilators. tv (ntsc) famously used a 35.8mhz oscilator which is most decidedly not derived from mains frequency, and this is not new technology by any means (tv refresh rate was 29.97hz,  not 30). more modern crt monitors had programmable oscillators to give them more flexibility in the video modes they supported. mians frequencies were still an issue, but there are more ways to deal with that noise than syncing to mains.

Edited June 24, 2023 by Nuke

[magnemoe]

On 6/24/2023 at 4:27 PM, Nuke said:

initially perhaps, but having used several crt monitors a wide array of refresh rates and resolutions were possible. clocks have been derived from crystal oscilators. tv (ntsc) famously used a 35.8mhz oscilator which is most decidedly not derived from mains frequency, and this is not new technology by any means (tv refresh rate was 29.97hz,  not 30). more modern crt monitors had programmable oscillators to give them more flexibility in the video modes they supported. mians frequencies were still an issue, but there are more ways to deal with that noise than syncing to mains.

I know the old CRT TV's used the power frequency to control their frame rate. I belive early pc monitors has few framerate options, think it was 30 and 60 Hz. 
Remember that Amiga required monitors with more adjustable framerate and they was more expensive than the standard PC ones. 
You also explaned why some monitors has 59.951 Hz refresh rate like my monitors at work.  

[Nuke]

4 hours ago, magnemoe said:

I know the old CRT TV's used the power frequency to control their frame rate. I belive early pc monitors has few framerate options, think it was 30 and 60 Hz. 
Remember that Amiga required monitors with more adjustable framerate and they was more expensive than the standard PC ones. 
You also explaned why some monitors has 59.951 Hz refresh rate like my monitors at work.  

its just a lot easier to derive all your clocks from a higher clock than a lower one. you can sync to a clock but that requires extra circuitry. if instead your pixel clock is an integer multiple of your line clock, and the line clock is an integer multiple of your framerate, then you dont need to worry about sync. it then just becomes a matter of counting clocks and you can get all your timing signals off of a crystal-driven reference clock and a single clock divider ic. tv also has the trouble of sinking up to a radio signal which is why they use such weird base frequencies. 

Edited June 26, 2023 by Nuke

[Zozaf Kerman]

As a FPS game player, I can confidently say that higher fps is an advantage. The difference between 60-> 165, 240,360, uncapped is astounding. You probably will be on the same levels as other players at say, 165, but if you can have the smoothness of a 360 fps (even if your monitor refresh rate is 165 or lower), than you will have a noticeable difference and a definite advantage over low-fps (60) players.