Frame Rates...Stop Kidding Yourselves

[NHawk]

Those of you who think you're getting 200+ fps are most likely kidding yourseves. Simply because of  a limiting factor which I'll try to explain as simply as possible, and I'll use nice even numbers to keep it that way.

First, take into account screen refresh rate. Let's say you have your screen refresh rate set to 100Hz. That means your screen is being redrawn 100 times per second. It can't be redrawn any faster than that. Period.

Now, you check your frame rate and your system says you're getting 200fps. You think WOW this is great! Well, guess again.

What the system is telling you is that the video card is sending information to the screen at 200fps. BUT, what you are actually seeing is 100fps. The screen is incapable of redrawing the screen at 200fps because of the limiting refresh rate.

What's happening to the other 100 frames? They are most likely being lost completely. The system is displaying every other frame.

Are there monitors able to refresh at 200Hz? Probably, but most of us don't own one.

Now, I'll leave this to debate and bow out of the conversation.

[mos]

k

[zmeg]

NHAWK, what you say is very true, but can you explain this?

[Replicant]

zmeg, you probably have vsync disabled which highers the frame rate in game but is generally not recommended (according to Skuzzy).

[mrblack]

Photoshop:aok

[Ack-Ack]

Originally posted by NHawk
Those of you who think you're getting 200+ fps are most likely kidding yourseves. Simply because of  a limiting factor which I'll try to explain as simply as possible, and I'll use nice even numbers to keep it that way.

First, take into account screen refresh rate. Let's say you have your screen refresh rate set to 100Hz. That means your screen is being redrawn 100 times per second. It can't be redrawn any faster than that. Period.

Now, you check your frame rate and your system says you're getting 200fps. You think WOW this is great! Well, guess again.

What the system is telling you is that the video card is sending information to the screen at 200fps. BUT, what you are actually seeing is 100fps. The screen is incapable of redrawing the screen at 200fps because of the limiting refresh rate.

What's happening to the other 100 frames? They are most likely being lost completely. The system is displaying every other frame.

Are there monitors able to refresh at 200Hz? Probably, but most of us don't own one.

Now, I'll leave this to debate and bow out of the conversation.

You're right and you're wrong.  You're right if the player has Vsync enabled which ties the frame rates to the refresh rate of the monitor.  But if the player has Vsync disabled then the frame rates can be higher than the refresh rate since it's no longer tied to the refresh rate.  That is why you see stuff like texture ripping and other graphic anomolies with Vsync disabled.

Lesson over.


Ack-Ack

[Innominate]

It's all semantics.

The number of frames displayed can never exceed the monitors refresh rate.

The number of frames processed is limited only by the cpu/video card.  (Vsync waits in between frames long enough for the monitor to finish refreshing)

For the most part the only use of vsync off is for benchmarking.  As mentioned, it will cause annoying artifacts, especially with a lot of movement.

[Blackbal]

Actually...

What happens when you turn vsync off is that the video card doesn't synchronize it's output to the monitor's refresh rate.  The result being that those extra frames are being drawn, just as fragments.  So, for example, if you have 200 fps at a 100 Hz. (100 fps) refresh rate, every frame the monitor draws would contain 2-3 pieces.  In the simplest case the top half would be from the first video card rendered frame, the bottom half would be from the second frame.  The downside to this is that fast motion in the scene (or rapidly changing colors) would leave a noticable separation between the halves of the screen.  Of course if your refresh rate is high enough you'd be unlikely to notice it during gameplay, but screenshots would catch it.

The point is there isn't any real benefit from turning vsync off other than for benchmarking.  So maximum effective framerate is capped by your monitor's refresh rate.   Adding to that, typical monitor refresh rates meet or exceed the maximum speed the human eye can process the images anyway.

[Siaf__csf]

Claiming that fps over monitor refresh rate would be useless is total BS. The true fps varies a lot during gameplay and the fluctuations may cause noticeable lag regardless of how high the fps seems to be at one given time.

Some players think that the eye can't see anything past 30fps.. However 30fps is way too slow during fast movements which are typical during gaming. The eyesight part is not all there is to it though.

When your fps varies, also your game performance varies. Therefore when your fps drops noticeably it also affects the way the game responses to your commands. It affects the way your packets are being sent to the server, it affects your whole game performance.

Therefore a player who gets a constant 200fps is FAR better off than a player who hardly gets 85 (with or without monitor refresh) and freezes up during a heavy battle.

[Ecliptik]

FPS rates over your refresh rate won't make a difference visibly (most framerates over ~30 won't make much of a difference), it's just a measure of performance.  

The whole point of getting as many frames per second drawn to the backbuffer as possible is that framerates are going to drop when more polygons and effects are being rendered, or if more complex physics calculations are occurring.  If you're getting 200 fps in a low detail situation, it doesn't matter if you don't see a difference between 200 and 60 fps.  200 fps is still much preferable, because it means that your system is less likely to drop below the 30 fps threshold during a stressful high-detail scene.

[Innominate]

Originally posted by Siaf__csf

Some players think that the eye can't see anything past 30fps.. However 30fps is way too slow during fast movements which are typical during gaming. The eyesight part is not all there is to it though.

It is true that the eye can't see more than 30fps.  Thats actually why a higher framerate is preferable.

With film running at 24fps, each frame represents (almost) 1/24th of a second.  Shutter opens, and any movement during that fraction of a second is recorded as a blur.  That blur gives the impression of smooth movement.  However, in a computer game, each frame only represents one discrete moment in time, making the transitions between frames appear jumpy.  With higher framerates, multiple frames add up over those fractions of a second to produce what to our eyes is a motion blur effect.

[Skuzzy]

Actually Siaf, what has been said is fairly accurate.

There are a number of factors involved with accurate frame draws as it relates to FPS.  A video card has many options available to determine what should be drawn on the display at any given moment.
When a game displays the FPS, it is displaying the rate at which it can render a frame.  Just because a game renders it, does not mean that frame is actually being displayed on the video display.

Now it gets complicated.  When vsync is enabled, you are assured that every frame rendered is displayed, as long as the video subsystem properly honors vsync.  So what is a game doing when it cannot shove data to the video card during a frame draw?
Well, it depends on how many frame buffers a game allocates and if the frame buffers are full or not when the game wants to render a frame.  It also depends on how the video subsystem (hardware/driver) decides  it wants to handle it.
Sometimes a video card can stall the data delivery so a frame will not be missed, sometimes it might throw away a frame buffer to allow the game to continue.  Really hard to know as it is dependent on the video subsystem.
Most of the time a video subsystem will make the best attempt to make sure the video frames are rendered so they do not miss any data, which keeps the video smooth and accurate.

Without vsync, a video subsystem has several options available.  It can overwrite the video frame, which will typically cause 'tearing' in the video display due to mismatched frames being partially overlayed.
The video susbsystem may opt to finish a current frame buffer and overwrite previous buffers, which can cause some jerkiness in the motion of objects, but this method eliminates the 'tearing' effect.
A game could also send the same frame over and over again, if the update information is not available for the next frame.  This last item can lead to some intersting visuals.  For instance, in an online game, the object in your view needs a packet update from a server to be placed accurately in its environment.  If you are running insane frame rates, your player/object could get updatred many times while game code simply extrapolates the remote object position.  Suddenly a packet update arrives and the extrapolation may not have been accurate and the remote object jumps.
Your position, which the remote player has not gotten yet coupld also jump as while you are running insane frame rates and your object has been moving around, the remote player does not see it until he gets a packet update.
Now, both of you are out of sync, which can cause perception of lag, when in fact, it is a video synchronization problem and may not have a thing to do with lag.  This can be more exaggerated with very high CPU speeds as well.

Keep in mind, I am not specifically talking about Aces High.  Just the overall effect running without vsync can have on a multi-player game.

[Siaf__csf]

Skuzzy I think you misinterpreted my message. I was saying that 30fps is not enough for a fluid gameplay experience..

Even in the movies the low shutter rate really bothers me when there are fast movements, you can clearly see flickering in the picture during fast camera runs.

When a game of mine runs at 30fps, I feel it to be sluggish, low responsive and generally unplayable. That doesn't have anything to do with actual visual information, even. It doesn't bother me if the screen is a tad jumpy, but response problems do.

I know all about the technology you explained, I did some studying already back at WB when I noticed large differencies between 2D and 3D hit accuracy as well as vsync enabled and disabled.

What I didn't know was that the game can actually draw prediction calculated movements if the screen needs refreshing and is not dependent to some fixed synchronisation. So basically what you're saying is that if a person runs at 700fps a moment of netlag can cause 7 times the jump on his screen compared to a person who runs at 100fps? That would well explain the 'rubber bullet' syndrome with vsync off, though.

That being said, it's downright wrong to state gamers do not need fps rates past 30, 60 or whatever in order to get a good performance from a game. The truth is that (with vsync disabled) your framerates will need to be skyhigh in most if not all games in order to be able to handle the parts of the game where a lot of action, polygons and movement is being displayed.

You play with vsync on - but you need to have that 'hidden' reserve in performance.

[straffo]

Originally posted by Siaf__csf
You play with vsync on - but you need to have that 'hidden' reserve in performance.

Right on spot !

[2Hawks]

I would lend my .02 in support of Siaf.

Try holding a Quake Lan Party and defeating anyone with a higher FPS that you.   Gonna be WAY hard if s/he is halfway decent.

In AH or Q3A, If they see you before you see them your dead.  Bandwidth issues share this issue. I have seemed to have noticed faster connects see you spawn first, and nail you before all the cons have even appeared on your end.

The faster the better. No excemptions. Get HT to upgade your workstation and stop feeding you a line.


Here's a question for everyone tho...

Were the screenshots based on CRT screens or LCD? I haven't played with them much, but  aren't the LCD displays un-inhibited by a refresh Rate since it's function can be directly manipulated rather than a directed electron stream painting a pigmented phosphor screen?