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  • [Tony Tamasi]: Hi this is Tony Tamasi with NVIDIA,

  • here to give you a little background on a video we put out recently

  • about high-framerate gaming and the benefits

  • to latency, smoothness, and animation.

  • Before we dive into this in too much depth, let's first

  • understand a couple of the fundamental concepts.

  • That being framerate, which is typically your GPU,

  • and the display rate or Hertz, which is typically

  • your monitor's ability to refresh the screen.

  • The animation that you see here is a demonstration

  • of the monitor and the GPU's rate.

  • The top most graph is showing the rate at which the monitor is refreshing

  • the screen, which is measured in Hertz.

  • On the bottom you're seeing the graph of the GPU's render rate or framerate.

  • While it might average 60 frames per second,

  • some frames are faster, and some frames are slower.

  • and they don't perfectly align.

  • For high-framerate gaming, you want both of these to be as high as possible.

  • Before we dive into our topics in detail,

  • one clarification I should make is we've made a simplification.

  • We've made the assumption that our GPU rate, framerate,

  • and our display rate, Hertz, are the same thing.

  • While this doesn't typically happen in the real world, this is a simplification

  • we've made to help with the fundamental concepts and understanding.

  • One of the first topics we want to talk about is animation smoothness.

  • One of the things you'll notice that is a great difference

  • between a 60 FPS and a 240 FPS game

  • is the smoothness of the animation.

  • And that's because in each case the rates of the

  • animation updates are happening at different frequencies.

  • 60 frame updates happen once every 60th of a second.

  • Which means that as an animation is stepping through,

  • it only has 60 times every second to update its position,

  • which means the steps are larger.

  • At the 240 framerate, the updates are happening 4 times as frequently,

  • once every 240th times per second.

  • Which means that the size of the animation steps are smaller,

  • which makes the animation feel much smoother.

  • Taking a look at this top and bottom, you can see that 60 frame

  • and 240 framerate video have a very different feel in terms of smoothness.

  • The 60 framerate video has much larger animation steps

  • making it feel much less smooth than the 240 FPS video.

  • Next up is Ghosting. Ghosting is that property

  • we've all experienced when you see this kind of faint blur

  • that looks like it's trailing an object in motion.

  • That's actually a side effect to our property of our typical

  • modern flat-panel displays because they have an update rate.

  • Looking at our bouncing ball animation, you can see

  • that the step size is fairly large, which means that

  • smear behind the object is fairly pronounced.

  • If we look at the animation now at 240 Hertz,

  • you can see the step size is much smaller, which makes the ghosting much

  • less pronounced and therefore much less distracting.

  • Looking at this in-game in CS:GO, our character is moving from right to left.

  • At 60 Hertz you can see the animation steps are fairly large,

  • so the ghosting is fairly pronounced.

  • On the right-hand side, you can see the character moving at 240 frames per second,

  • and the steps are much smaller, so the ghosting much less pronounced

  • and therefore much less distracting.

  • To understand our next topic 'Tearing,' it's important to understand

  • another concept which is VSync.

  • VSync is the synchronization, or lack of, between the display and the GPU.

  • In the VSync ON scenario, the display and the GPU are locked,

  • which means the GPU only presents completed frames on the display.

  • In the VSync OFF scenario, there is no waiting,

  • which means the display is going to continue updating and it's going to

  • grab the frame at whatever state the GPU happens to have it in,

  • which could be sometimes partial frames, and then present it.

  • That partial frame appears on your screen as a tear.

  • Why would you accept tearing? Well,

  • one of the advantages of VSync OFF is that the GPU can render

  • as fast as it possibly can, which can make the game feel much more responsive.

  • We've made some simplifications here today around VSync for understanding.

  • We'll get into more complex topics like G-Sync

  • and variable refresh rate at a later date.

  • As you can see here in the animation, the lack of synchronization between

  • the GPU and the display causes tearing.

  • The GPU is required to present an incomplete frame.

  • the size of that tear that you see there is determined by the animation step.

  • At lower framerates, those steps are fairly large,

  • so tearing can be quite pronounced.

  • At higher framerates, the steps are much more frequent, so they're smaller.

  • So the tears are much less pronounced and therefore less distracting.

  • Looking at tears in CS:GO, we can see here as we zoom in on the

  • vertical brown tower, the tears on the top are much smaller

  • than the tears at the bottom at 60 Hertz because the animation steps

  • are much more frequent and therefore the tearing much less

  • pronounced at 240 Hertz.

  • Our final topic is system latency, which is a bit more complicated.

  • System latency is typically known as that mouse click to muzzle flash

  • or that motion to photon latency.

  • It is not network latency, which is typically how your computer communicates

  • over the internet to a back-end game server, sometimes referred to as lag.

  • Taking a look at our game pipeline, we have 60 FPS example.

  • And again for simplification, we've decided to set

  • the GPU rate and the CPU rate to be the same.

  • So in this case, they're both at 60 FPS.

  • That means the blue bar here, the CPU, takes 60 milliseconds

  • at 60 FPS to do its work.

  • It then hands off that frame to the GPU, which also takes 60 milliseconds

  • at 60 FPS to do its work.

  • The gray bar that you see there is the amount of time

  • it actually takes the display to update and show you that frame.

  • At 240 FPS everything speeds up.

  • Our CPU work, our GPU work, and our display work

  • are all roughly four times as fast.

  • So at 240 FPS, your system latency is one quarter of the time.

  • Using a single frame as an example, we have a fast system here on the top.

  • and a slower system at the bottom. They're both doing the same work

  • which is to render and produce a single frame.

  • The fast system is producing CPU work, GPU work, and display work sooner

  • than that slower system doing the same work.

  • The difference between those two is the difference in overall system latency,

  • which is felt as reduced input delay.

  • Which is mouse click to muzzle flash or motion to photon.

  • Okay. To bring this all home, let's take a look at an example

  • of system latency in CS:GO.

  • At the top we have fast system running at 240 FPS,

  • and at the bottom at a 60 FPS system.

  • They're both receiving updates from the network at the same time,

  • but the faster system processes that work faster resulting in lower latency.

  • And the slower system takes longer.

  • Denotated here by this vertical bar, the difference between a 240 FPS system

  • and a 60 FPS system is quite pronounced.

  • That difference is the difference in system latency

  • which lets you, as the player, react faster.

  • So we've explained some of the fundamental concepts,

  • but why is this important? Why does high framerate matter?

  • What we have here is a chart that plots the correlation

  • between high framerate and success in a first-person shooter.

  • In this case what we've done is measured Kill/Death ratios

  • in Battle Royale games like Fortnite and PUBG.

  • And as you can see there's a correlation between

  • higher framerates and higher Kill/Death ratios.

  • If you're interested in the study, please check out the link below.

  • We hope you've found our video on high-framerate gaming informative.

  • Please leave your thoughts in our comments below and be sure to check out

  • our slow-mo, high-framerate video. Thanks for watching.

[Tony Tamasi]: Hi this is Tony Tamasi with NVIDIA,

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為什麼高刷新率如此重要(Why High FPS Matters)

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    張軒軒 發佈於 2022 年 01 月 13 日
影片單字