What is the benefit of capping your max fps (frames/sec)?

[psteng19]

Some FPS (first person shooters) will allow you to cap your maximum frames per second (fps).
What is the benefit or purpose behind this?
I assume it was put there for good reason.

Is HL2/CS:Source, I will get anywhere from 40 FPS all the way up to 180 FPS.
Should I cap my max fps to a certain number to prevent this huge variation?

 

[thelanx]

Large fluctuations of fps will make things choppy during that fluctuation. Even if you go from 180fps to 60fps, and normally 60fps seems smooth, most ppl can tell the difference btw 180 and 60 fps. Because you are used to 180 fps, a sudden drop to 60 fps will seem kind of choppy and can throw you off. You should cap it at a fps that stays pretty much constant throughout the game.

 

[mugs]

What's the point of 180 FPS when monitors don't refresh nearly that quickly? Or am I wrong?

 

[Malak]

Originally posted by: mugs
What's the point of 180 FPS when monitors don't refresh nearly that quickly? Or am I wrong?

No you aren't wrong. A monitor won't display higher than it's refresh rate. So for instance, my refresh rate is 85, so the most fps I will actually see is 85. The video card may output more, but it won't display it. I would suggest setting a cap at the limit of your monitor, as it is pointless for the video card to try and go higher.

 

[Modeps]

Originally posted by: mugs
What's the point of 180 FPS when monitors don't refresh nearly that quickly? Or am I wrong?

you're obviously wrong, I mean why else would hardware dorks care if they got 200 fps??

 

[DaveSimmons]

For single-player games, capping the FPS leaves more CPU time available for AI and other background processing.

Some games may use successive / iterative refinement, where you create a fast but bad solution to a problem, then if time permits you create better solutions to replace the initial one. If the CPU is spending all its time feeding the video card, there might not be time to complete the better solution (= smarter AI).

A cap can also slightly smooth out the transitions between low and high FPS. For example with a cap of 60, instead of (90, 50, 90) you might get (60, 51, 60). Because you weren't rendering extra frames in the fast part, the first frame of the slow part is finished sooner.

 

[thelanx]

In quake3 the in game physics were dependent upon fps, so have an fps of 125 would make you jump just a bit higher. Doom3 is fps capped at 60 to avoid such an exploit, but that is a reason for fps capping above your refresh rate.

 

[AdamSnow]

Good information!!

I was not aware of this.

 

[psteng19]

Originally posted by: malak

Originally posted by: mugs
What's the point of 180 FPS when monitors don't refresh nearly that quickly? Or am I wrong?

No you aren't wrong. A monitor won't display higher than it's refresh rate. So for instance, my refresh rate is 85, so the most fps I will actually see is 85. The video card may output more, but it won't display it. I would suggest setting a cap at the limit of your monitor, as it is pointless for the video card to try and go higher.

You have Vsync enabled.




So it sounds like it's recommended to to set a cap that's somewhat in the playable and tolerable range.

 

[Malak]

Originally posted by: thelanx
In quake3 the in game physics were dependent upon fps, so have an fps of 125 would make you jump just a bit higher. Doom3 is fps capped at 60 to avoid such an exploit, but that is a reason for fps capping above your refresh rate.

That's a bug in the engine that was exploited soooo much. Although the exploit doesn't seem to work in any other quake3 game that I'm aware of.

 

[Lord Athlon]

For some games , it may prevent tearing if your FPS exceed your screen refresh rate.

I had to turn VSync ON in KOTOR for that reason

 

[BlueWeasel]

So what's the recommended max FPS setting for HL2?

Right now, mine must be capped at 100, as I never see my FPS go higher than 99 and the range varies from 40 to 99. The slowdown is noticeable when it drops suddenly from 99 to 40. Would reducing my max FPS down from 100 make the game "feel" smoother?

I can't complain, though. The game runs very well on my 9800 @ XT speeds, so I'm happy.

 

[duragezic]

If you are capped at 60 fps, 75 fps, 85 fps, etc., then turn Vsync off if you want higher fps, although I doubt it matters much at already high numbers.

Maybe FPS is limited by default in certain games for smoother internet play?

 

[CPA]

two questions:

1) how do you cap your framerate?

2) how do you turn off VSync?

 

[BFG10K]

What is the benefit or purpose behind this?

Nothing except possibly a little reduced tearing. All you're doing is wasting the performance potential of your rig. Usually what happens is that the game engine takes priority and the rendering is done with any spare CPU cycles that are left after that.

Should I cap my max fps to a certain number to prevent this huge variation?

A variation isn't necessarily a problem, it's when the minimum drops below a certain threshold and you detect a slowdown. All capping will do is ensure you experienence a constant slideshow instead of a varying one. In fact the likes of vsync will actually cripple your minimum framerate at times so it's definitely a bad idea.

What's the point of 180 FPS when monitors don't refresh nearly that quickly?

You'll still get partial frames which translates to better input response and better visual feedback.

1) how do you cap your framerate?

It varies by game.

2) how do you turn off VSync?

Again it varies by game. You can also use your driver control panel.

 

[BlueWeasel]

Originally posted by: CPA
two questions:

1) how do you cap your framerate?

2) how do you turn off VSync?

For which game? If HL2, then

(1) Go under the console (~) and type max_FPS
(2) Go under Options --> Video --> Advanced --> Enable/disable vertical sync

 

[warcrow]

Originally posted by: DaveSimmons
For single-player games, capping the FPS leaves more CPU time available for AI and other background processing.

Some games may use successive / iterative refinement, where you create a fast but bad solution to a problem, then if time permits you create better solutions to replace the initial one. If the CPU is spending all its time feeding the video card, there might not be time to complete the better solution (= smarter AI).

A cap can also slightly smooth out the transitions between low and high FPS. For example with a cap of 60, instead of (90, 50, 90) you might get (60, 51, 60). Because you weren't rendering extra frames in the fast part, the first frame of the slow part is finished sooner.

Well said....

 

[raildogg]

i put my fps's to the highest level in whichever i play

 

[Allio]

There is NO reason to turn off VSync unless you're being locked at a framerate below your refresh rate that you know you isn't the max your system can do. These circumstances are pretty rare, so just leave it on - it looks a whole lot better.

 

[abaez]

No, turn it off.

 

[boran]

Vsync on or off is subjective, personally I cant stand Vsync off (I really see the tearing, and a lot of it) some other peoples dont see it.

So it's simple, turn it off, if you see any tearing, turn it back on.

Off will give better performance once you drop below your sync ratio, say youve got a refresh rate of 60 (I know normally it's higher, but 60 calculates better than 85) and your PC can render 45 fps, then you'll get 30 (60/2) if your PC can render 29, you'll get 20 (60/3) if your Pc can render 19, you'll get 15 (60/4)

As you can see Vsync on is not good if you get suboptimal performance (and is the reason why I havent played halflife2 or doom3 yet with my sucky 3D card )

Those examples above are for a constant fps, if fps fluctuates so will your synced fps, in real life it's not that simple, but with vsync on you will always have less than your rig can actually render.

 

[tranceport]

Originally posted by: malak

Originally posted by: mugs
What's the point of 180 FPS when monitors don't refresh nearly that quickly? Or am I wrong?

No you aren't wrong. A monitor won't display higher than it's refresh rate. So for instance, my refresh rate is 85, so the most fps I will actually see is 85. The video card may output more, but it won't display it. I would suggest setting a cap at the limit of your monitor, as it is pointless for the video card to try and go higher.

You calculate the frames per second a monitor can display by taking the response time in milliseconds and dividing it into 1000.

For instance a 16 ms response time will give you 62.5 FPS.

 

[pat8]

Slightly off topic ....

I've got a ATI X800 XT with CAT 5.1 drivers. Running HL2 I can't get over 60 fps (which is my LCD monitor refresh rate). I've tried turning off Vsync in HL2, setting my max fps to 300, turning off vsync in the ATI drivers, trying different ATI drivers (4.9), etc, etc). Can't change it no matter what I do...

Any thoughts, what have i missed ?

PS other apps are fine, seem to be HL2 related.