3 ms·

> It’s just interesting to me that we have 500hz monitors, yet games are still coming out that only run at ~70fps on a 3080, etc. Of course new games are runni

by dahart 3y ago

> It’s just interesting to me that we have 500hz monitors, yet games are still coming out that only run at ~70fps on a 3080, etc. Of course new games are running at 70 fps. Most games are absolutely not designed for 500hz, and have zero reason to do that. Cs:go wan’t designed for 500fps, I bet the designers of cs:go never intended people to play at 500fps, or even imagined that would ever happen; it wasn’t possible when the game came out. There’s a good reason to never go above 70fps: human perception experts tend to agree that our visual system gives us quickly diminishing returns above 60fps, we can’t really see things any faster than that, so I’m quite skeptical that 500fps is necessary. The whole reason 500fps is useful for competitive esports gaming is to reduce latency, not really to keep increasing frame rates forever. Because games are triple-buffering and sometimes monitors are too, and there’s another frame of latency for controller inputs to be recognized, you might still have 10ms or more of latency between controller input and changes on-screen, even if your game is rendering at 500hz. This means you could get away with 100fps if you had zero latency. When your fps is 60hz and there’s 5 frames of latency, you don’t see responses to your controller until almost 100ms later(!). It’s been about a decade since I was a game dev, but it’s wild to me that anyone would want 500 fps, or that any games would aim for that. This gives you a grand total of 2 milliseconds do to everything, gameplay + animation + physics + audio + rendering. It’s not a lot of time, and you have to compromise your visuals and rendering (by 10x!) in order to achieve that frame rate. Looks like a lot of new gaming monitors are 144hz, and these new 240/360/480hz monitors are pretty extreme and still a bit rare. > I understand that some games purposefully limit FPS for physics calculations, but there are many that do not. FWIW, this isn’t the way I’d frame it, it’s kinda misleading. Very few games are purposefully limiting FPS for the sake of slowing it down. All games, however, have a budget. There are always limited compute & render resources, and both game devs and players want the highest quality available for their budget. Until very recently most games aimed for 30fps, and only really fast twitchy games went for a relatively very smooth 60fps. The games that went for 60 had to cut their polygon counts and physics and gameplay in half in order to achieve high frame rate, so you are totally trading away a richer experience in favor of high frame rates. Only certain kinds of games should even try to do that.

Mawr 3y ago
Looks like you were specifically a console game dev? PC games have not aimed for 30fps either ever or at least for the last 2 decades. Consoles are hilariously far behind PC in this aspect. The whole "science says the human eye cannot see beyond 30fps :)" is actually a very old meme at this point. You are correct that high FPS/Hz is about decreasing latency, but you underestimate the importance of it. 144hz is a very clear improvement over 60hz and the PC ecosystem is going to move over to it as a new standard relatively soon. You don't need to be playing a hyper-competitive FPS to notice it either, any game with significant movement will do. > Because games are triple-buffering and sometimes monitors are too, and there’s another frame of latency for controller inputs to be recognized, you might still have 10ms or more of latency between controller input and changes on-screen, even if your game is rendering at 500hz. This means you could get away with 100fps if you had zero latency. When your fps is 60hz and there’s 5 frames of latency, you don’t see responses to your controller until almost 100ms later(!). You're assuming VSync or something. There's no guarantee that the input will line up with the next frame, so an input latency of 10ms while running at 100 fps equals a worst-case latency of roughly 20ms, not 10ms. That's why the higher fps & hz numbers really matter.
- dahart 3y ago
  Guilty as charged, yes you’re right I was a console game dev. Fair enough, yes PCs are way ahead of consoles and I overstated the perceptual limits of frame rates. I didn’t really mean to suggest that competitive twitchy PC games have no reason to go above 60fps, I meant that there’s a whole swath of other kinds of games that don’t need it (consoles, mobile, puzzle games, etc. etc.). I was reacting more to the idea of 500fps which is really far above 144hz, and the implied suggestion by top comment that maybe even 500 isn’t enough and that everything should be trying go there. > an input latency of 10ms while running at 100fps equals a worst-case latency of roughly 20ms, not 10ms. That’s why the higher fps & hz numbers really matter. Yes exactly, I agree and this was the point I was trying and I guess failing to make. Latency is typically multiple frames, so at 100hz, latency can easily be longer than known science-meme perception times. Even with vsync there’s up to one frame to recognize inputs, then another frame to produce new game state & submit the render, then 1 or 2 more for double or triple buffering, then maybe supersampling and/or denoising, then whatever the monitor does, and I might be missing some steps that add latency. So I suspect 500hz has nothing to do with seeing smoother motion compared to 144hz, and everything to do with getting overall control latency down to below, say, 10ms. Does that really work though? Does CS:GO and do other modern games poll the controller at the display refresh rate? I know it’s pretty common for a lot of games to decouple rendering from game state. That can mean a lot of different things, but one of the implications might be that controller latency is limited to one or two frames of, say, 60hz game state updates, followed by 3-5 frames of 500hz display refresh. Is latency in today’s PC games limited by the game state update, regardless of what the display refresh rate is? I’m curious where the perceptual limits really are, and what the max framerate we actually need is. Suppose an imaginary world where worst case input-to-screen latency is 2 frames. Then in that case, how high should the FPS be? What if there was zero latency - like if the next rendered frame magically reflected mid-frame controller inputs and magically displayed with no latency - then what should the ideal FPS be? Would there be any benefit to going higher than 144, or would we be wasting electrons?

by dahart 3y ago

Mawr 3y ago

Looks like you were specifically a console game dev? PC games have not aimed for 30fps either ever or at least for the last 2 decades. Consoles are hilariously far behind PC in this aspect. The whole "science says the human eye cannot see beyond 30fps :)" is actually a very old meme at this point. You are correct that high FPS/Hz is about decreasing latency, but you underestimate the importance of it. 144hz is a very clear improvement over 60hz and the PC ecosystem is going to move over to it as a new standard relatively soon. You don't need to be playing a hyper-competitive FPS to notice it either, any game with significant movement will do. > Because games are triple-buffering and sometimes monitors are too, and there’s another frame of latency for controller inputs to be recognized, you might still have 10ms or more of latency between controller input and changes on-screen, even if your game is rendering at 500hz. This means you could get away with 100fps if you had zero latency. When your fps is 60hz and there’s 5 frames of latency, you don’t see responses to your controller until almost 100ms later(!). You're assuming VSync or something. There's no guarantee that the input will line up with the next frame, so an input latency of 10ms while running at 100 fps equals a worst-case latency of roughly 20ms, not 10ms. That's why the higher fps & hz numbers really matter.

dahart 3y ago
Guilty as charged, yes you’re right I was a console game dev. Fair enough, yes PCs are way ahead of consoles and I overstated the perceptual limits of frame rates. I didn’t really mean to suggest that competitive twitchy PC games have no reason to go above 60fps, I meant that there’s a whole swath of other kinds of games that don’t need it (consoles, mobile, puzzle games, etc. etc.). I was reacting more to the idea of 500fps which is really far above 144hz, and the implied suggestion by top comment that maybe even 500 isn’t enough and that everything should be trying go there. > an input latency of 10ms while running at 100fps equals a worst-case latency of roughly 20ms, not 10ms. That’s why the higher fps & hz numbers really matter. Yes exactly, I agree and this was the point I was trying and I guess failing to make. Latency is typically multiple frames, so at 100hz, latency can easily be longer than known science-meme perception times. Even with vsync there’s up to one frame to recognize inputs, then another frame to produce new game state & submit the render, then 1 or 2 more for double or triple buffering, then maybe supersampling and/or denoising, then whatever the monitor does, and I might be missing some steps that add latency. So I suspect 500hz has nothing to do with seeing smoother motion compared to 144hz, and everything to do with getting overall control latency down to below, say, 10ms. Does that really work though? Does CS:GO and do other modern games poll the controller at the display refresh rate? I know it’s pretty common for a lot of games to decouple rendering from game state. That can mean a lot of different things, but one of the implications might be that controller latency is limited to one or two frames of, say, 60hz game state updates, followed by 3-5 frames of 500hz display refresh. Is latency in today’s PC games limited by the game state update, regardless of what the display refresh rate is? I’m curious where the perceptual limits really are, and what the max framerate we actually need is. Suppose an imaginary world where worst case input-to-screen latency is 2 frames. Then in that case, how high should the FPS be? What if there was zero latency - like if the next rendered frame magically reflected mid-frame controller inputs and magically displayed with no latency - then what should the ideal FPS be? Would there be any benefit to going higher than 144, or would we be wasting electrons?