60fps, the magic number....

First a little explanation of refresh rates, this is seperate to the response time of an LCD and applies to both LCDs and CRTs. With CRTs refresh rate is extra important as it reduces headaches as to why this will become clear.

The refresh rate simply put is the number of frames the monitor can draw every second, this therefore limmits the benefit you get from higher FPS. If your running 60hz and getting 100fps you only see 60 of those per second.

This is where tearing a v-sync come in, if you monitor is drawing 60fps and is sent 100 by the gfx card, it will start drawing the next frame before completing the previous one creating a "tear" in the middle of the screen where the split occured. v-sync tries to keep the FPS at a ratio to the refresh rate (1:1 = 60fps, 1:2 = 30fps) to reduce this effect which is most notable on vertical edges.

An LCD is creating a picture all the time, the backlight is constantly on and shining through the liquid crystal so in effect the screen morphs to the next frame (the response time is how fast this happens), with a CRT the electron gun draws every frame as many times as the refresh rate, at 60hz for most people this will create a flickering, which while faint the eye picks up on and tries to see through it. The eye simply cant keep up and strains itself. At say 100hz the eye cant see the the flickering and the image is a complete illusion of a picture.

So why is 60fps the magic number? Simply because most LCDs (especially laptops) run at 60hz, therefore there is no reason to have a higher fps. This is one area where high refresh rate CRTs are better as they can have between 120-140hz allowing for VERY smooth gameplay.

 

Just to add to the post, Doom 3 is capped at 60fps as this is what the character animations were drawn at.

There is also triple buffering which when enabled allows for smoother gaming under vsync conditions. This can be enabled through the drivers for OpenGL games, but for DX games you'll have to get DX Tweaker.
http://www.ocworkbench.com/2006/articles/DXtweaker/ See here for some more info.

 

Quake 4 is based on the same engine as Doom 3 and is also capped at 60.

Thanks for the informative post Meaker.

 

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No problem, if I see some questions floating around or a similar topic I try and post things like this

 

Very informative post. Now one question: What benefit is there of running something at 60 fps if the human eye can only see 24fps?

 

http://amo.net/NT/02-21-01FPS.html

If you cant be arsed to read it, to sum up the lower quality of films and TV and the fact they are recorded allow motion blur, due to the MUCH higher quality for the size of computer monitors and that there is no motion blur you need a higher raw refresh rate.

Which is why you want higher than 60hz when there is not a continous image.

 

i can certainly see the difference between 25 and 60fps, lol

and for me this is why a "medium" spec GPU is enough in a laptop, they can do 60fps for most games, which as has just been described...is plenty

 

How do I amm "Monitor" or how can I see what my frame rates are when running games??

 

I almost always leave VSYNC on unless I'm benchmarking. If the app you're using is multi-threaded, that means the graphics driver will not lock the CPU up nearly as often drawing the image, so you can get better performance, especially when you need the extra CPU horsepower. This isn't as big of an issue with dual-core chips, but it's still a good reason to leave vsync on. It won't help making the computer compute frames that won't ever actually be shown on the display.

 

/\ Sooo what I need to run some kind of app to do it??...I'm really not familiar with it

 

www.fraps.com

Good post by the way... hehe

 

/\ Thanks ...

 

I play gta3 constant at 60fps when i put 4x AA on in the drivers (and framelimiter of in gta3). The fps are always between 58 and 62. It gave me a whole new experience. Now i love gta3!!!

 

the human eye can see 60 fps... its just movies that are in 24 fps and thats only some.

 

the best prove is to try it out for yourself

Run a game at 30fps and a game at 60 fps, you will see the difference.

If you have a high end GPU then gta3 is a good example. Play it first with the framelimiter on and after a few minutes play it with the framelimiter off.