Game Responsiveness is More Than Just Good Frame Rate

[Shamus Young]

Game Responsiveness is More Than Just Good Frame Rate

The idea of framerate being the most important aspect of game responsiveness is not necessarily true. Shamus tries to explain in detail.

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[Imperioratorex Caprae]

This is a point I've tried to make over and over but people just don't want to listen. They're obsessed with numbers and the higher those numbers are, well... you get the idea. FPS is nice, but it doesn't solve every problem.

 

[Amaror]

I don't really see how you think that rendering and post-processing somehow have nothing to do with framerate. Your framerate depends on your rendering-speed and post-processing-speed, etc. So in the end it IS the fps that matters, because it's what all these different operations come down to.

And of course the hardware like the monitor must be up to par to render high framerates.

Basically i don't get what your point is, it all seems pretty obvious to me.

 

[Seracen]

I get the concept of this article, however, in practice, this is not what I often deal with. An article like this would be used by game devs to justify shortchanging the production cycle and quality of their product. Then again, devs aren't the only ones that can be myopic about such things; they just take that short-shortsightedness to extremes far too often and easily.

 

[Kenjitsuka]

So, the whole stack is complex and multi-layered...
Hasn't that been like that ever since Windows 95-ish? DirectX etc. are old as heck...

Like Amaror I too don't see the point; if the game is capable of consistently hitting 60 FPS on your hardware then the entire stack is optimized/efficient enough to... well, do just that.

If the game can't handle 60 FPS but needs to set it's benchmark at 30 you get Ass Creed Unity.
Did you see the massive texture pop-in and many other problems that shite has (like going down to sub 20 FPS according to reports)?

So if someone can deliver on a promise of 60 FPS I'd take that as a great sign they did a good job on the whole game.
I don't care about anything else...

Also, how long have 60 FPS monitors and to lesser some degree TV's been the standard, Shamus? Many TV's are 100 or 120 Hertz noawadays, chap...

 

[Something Amyss]

This is a point I've tried to make over and over but people just don't want to listen. They're obsessed with numbers and the higher those numbers are, well... you get the idea. FPS is nice, but it doesn't solve every problem.

For some reason, I'm now picturing GTA V in 60 FPS, and people insisting those sluggish-ass controls are somehow improved by it. It's not bad coding, it's frame rate!

 

[Xeorm]

I don't really see how you think that rendering and post-processing somehow have nothing to do with framerate. Your framerate depends on your rendering-speed and post-processing-speed, etc. So in the end it IS the fps that matters, because it's what all these different operations come down to.

And of course the hardware like the monitor must be up to par to render high framerates.

Basically i don't get what your point is, it all seems pretty obvious to me.

You missed the point. It's quite possible to have a game run at a pretty steady 60 fps while still feeling laggy, because the frames are put out in a consistent speed, but lagged a little behind what they should be.

For example, at 60 fps, I have a frame every 17 ms. I press a button at frame 0. If it's really responsive, the game may be able to register and change the gamestate based on that button press by frame 1. But if it's sufficiently laggy I may not see that response until frames 2-4. So even though the game has a great framerate, the responsive will be majorly impaired.

 

[Albino Boo]

I don't really see how you think that rendering and post-processing somehow have nothing to do with framerate. Your framerate depends on your rendering-speed and post-processing-speed, etc. So in the end it IS the fps that matters, because it's what all these different operations come down to.

And of course the hardware like the monitor must be up to par to render high framerates.

Basically i don't get what your point is, it all seems pretty obvious to me.

The response time and refresh rate are not the same. The refresh rate is the number of times the image is displayed per second and the response time is how fast the pixels change colour. Its perfectly possible to have a high frame rate and a long response time . If your monitor or TV has a long response time it doesn't matter a damn what you FPS if the rate at which the hardware changes pixels is slow. If your display is slow, the rest does not matter. FPS is only measure of some bottlenecks not all.

 

[DrMcCoy]

So in the end it IS the fps that matters, because it's what all these different operations come down to.

No. This is not about raw speed, but about latency.

Like the delay between you playing your guitar and the input arriving in your audio recording, which can be really damn annoyingly high if your audio stack has high latency.

Or take an MMO as an example. Your internet connection might be very fast, which means you can push lots of data to and from a game server quickly. But there's another value you need to keep in mind: your ping, which is the latency, the amount of time it takes to reach the server. If that is too high, you will feel a lag, even though your connection is still very good for raw transfer speed. And, as you know there are physical limitations. No matter how fast your connection is, if you are in the US and the server you connect to is in Europe, you won't get the ping lower than a certain value (usually 100ms, I think).

 

[Albino Boo]

So, the whole stack is complex and multi-layered...
Hasn't that been like that ever since Windows 95-ish? DirectX etc. are old as heck...

Like Amaror I too don't see the point; if the game is capable of consistently hitting 60 FPS on your hardware then the entire stack is optimized/efficient enough to... well, do just that.

If the game can't handle 60 FPS but needs to set it's benchmark at 30 you get Ass Creed Unity.
Did you see the massive texture pop-in and many other problems that shite has (like going down to sub 20 FPS according to reports)?

So if someone can deliver on a promise of 60 FPS I'd take that as a great sign they did a good job on the whole game.
I don't care about anything else...

Also, how long have 60 FPS monitors and to lesser some degree TV's been the standard, Shamus? Many TV's are 100 or 120 Hertz nowadays, chap...

Full blown hardware wasn't in windows 95. The first windows product to have it was Windows NT and it went mainstream with win2k. Refresh rate is not the same as response time, it can be a number of passes before you TV changes the pixel.

 

[SKBPinkie]

Latency and FPS seem like different issues, though.

You'd want both to be good. It's not a "one vs the other"-type scenario.

 

[rofltehcat]

Shamus mentions that a huge part of the delay is coming from the frame buffer/queue (there may be 3 frames in front of the current frame waiting to be sent) and the monitor refresh rate play a huge role.

Does technology like G-Sync reduce that delay by a noticeable amount? Or are there better ways to reduce the delay?
(It sadly isn't likely spread because nvidia and amd not cooperating on sync standards but I've heard Linus talk about it on the WAN show and he seemed pretty convinced.)

 

[UNHchabo]

Shamus mentions that a huge part of the delay is coming from the frame buffer/queue (there may be 3 frames in front of the current frame waiting to be sent) and the monitor refresh rate play a huge role.

Does technology like G-Sync reduce that delay by a noticeable amount? Or are there better ways to reduce the delay?
(It sadly isn't likely spread because nvidia and amd not cooperating on sync standards but I've heard Linus talk about it on the WAN show and he seemed pretty convinced.)

Sort of. Most GPUs allow Frame Queuing, and this makes it so that the GPU is always rendering a frame or two ahead of what's being displayed. I think most of the time you can configure that in the driver software, and some people speculate about the best setting to use for any particular situation. (I know very little about this)

This is separate from V-Sync -- with V-Sync turned off, the GPU renders frames as fast as possible, and then starts displaying them immediately. Since our current displays are still backwards-compatible with CRTs, this means that the lines are drawn top-to-bottom at a fixed rate, so new frame boundaries are visible due to tearing.

With traditional V-Sync (double-buffered) and a GPU faster than needed, after the last frame is drawn the GPU starts working on the next one. When that's done, it goes to sleep until the next frame, and the display ends up drawing a frame that's nearly a frame old. Meanwhile, with triple-buffering the GPU keeps rendering frames, but the display takes the newest complete frame, so you don't have tearing, and the lag is less than with double-buffered V-Sync, but still more than V-Sync Off.

Most of my knowledge of the subject came from this article [http://www.anandtech.com/show/2794].

Dynamic refresh rate technologies draw the frame as soon as it's ready, so it means theoretically you have about the same lag compared with V-Sync Off, with no tearing (I haven't used it myself). Apparently VESA (the display standards body) has added "Adaptive Sync" to the DisplayPort 1.2a standard [http://www.vesa.org/news/vesa-adds-adaptive-sync-to-popular-displayport-video-standard/].

Hope that explains it well enough.

As for the main part of Shamus' article, this article [http://www.anandtech.com/show/2803] from Anandtech explains the lag involved pretty well.

 

[Flammablezeus]

Has anybody actually heard anybody else say that framerate is the most important aspect of game responsiveness? Don't get me wrong, it clearly is a big variable. However, claiming that to be the case isn't the same as saying that it's the most important aspect or that other aspects aren't important.

 

[Kahani]

Latency and FPS seem like different issues, though.

You'd want both to be good. It's not a "one vs the other"-type scenario.

Isn't that rather the point of the article? The problem is that of course you want both to be good, but almost all the focus is on framerate (and resolution) with latency barely getting any mention at all.

That said, to some extent it's understandable. Framerate is something developers can actually control, especially on consoles where the hardware is always a known quantity. But if you happen to have a crap display plugged into that console, there's absolutely nothing they can do about it. And given the limited options for things like wireless controllers, there's not a lot they can do about many of the other factors involved. So of course the marketing focusses on things that they actually have some control over. "Buy our game, it does 60fps" is somewhat better advertising than "Don't bother buying our game because you need to replace your shit TV before you'll notice anything special about it".

 

[Steve the Pocket]

Funny how nobody has thought to start marketing "gaming TVs" that emphasize low latency. Or maybe they do and I've somehow never heard of it.

 

[Zipa]

Shamus mentions that a huge part of the delay is coming from the frame buffer/queue (there may be 3 frames in front of the current frame waiting to be sent) and the monitor refresh rate play a huge role.

Does technology like G-Sync reduce that delay by a noticeable amount? Or are there better ways to reduce the delay?
(It sadly isn't likely spread because nvidia and amd not cooperating on sync standards but I've heard Linus talk about it on the WAN show and he seemed pretty convinced.)

As someone who bought a Gsync monitor very recently I can tell you it makes a massive difference. There is no stuttering and no screen tearing with games using Gsync. It also puts out an incredible 144hz refresh rate.

 

[Something Amyss]

But frames STILL matter.

When did Shamus say they didn't?

 

[Something Amyss]

Funny how nobody has thought to start marketing "gaming TVs" that emphasize low latency. Or maybe they do and I've somehow never heard of it.

What's so funny about that?