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Discussion Starter · #1 ·
I use my PC on my Samsung HPS5053 plasma (1366x768). I currently ouput 720p and let my fps run wild. On CoD4 I average about 80fps, peak just over 100. I did notice when I sync each frame (game option, steady at 60fps) motion is smooth, but I'm curious if I am also losing a bit of speed/response?
 

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Syncing each frame will reduce "screen tear". This is the jagged line you see when panning your viewpoint to the right or left (commonly seen in first person shooters).


I'm not sure what you mean by "losing a bit of speed/response". It does use a little extra power from the video card to sync the frames, but video cards nowadays don't see this impact hardly at all. I have heard there are games that give people an advantage (like in Unreal Tournament 3 it lets you jump farther for some reason), but often this is from poor coding and doesn't really give you better "speed/response".
 

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Discussion Starter · #3 ·
All I meant by "reduce speed/response" is introduce minor lag that wouldn't be there otherwise. It seems like it would, but I don't know. I wondered if anyone had hard facts about it.
 

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Having vsynch disabled means you're rendering as fast you can, and image tearing usually results because your display ends up showing partial frames. You're also generating more heat and using more juice since your hardware is always pumping out as many frames as it possibly can.


Enabling vsynch will cause your framerate to be capped at your refresh rate.


Then one of two things will also happen with vsynch enabled:


1. Double buffering is used. This means no increased lag but your framerate is always a multiple of your refresh rate. Fore example, at a 60 Hz refresh rate, your framerate will drop to 30 fps if it can't sustain 60 fps, then 15 fps if it can't sustain 30 fps, etc. There is no in between and the sudden large changes in fps can result in things being a bit "stuttery" if it happens frequently.


2. Triple buffering is used. This will result in a slight input delay (you are one extra frame "behind") but your framerate is not limited to multiples of your refresh rate. Your framerate can fall anywhere below your refresh rate and fps fluctuations will be far smoother. For example, if your rig can turn a solid 55-60 fps, that's exactly what will be displayed, as opposed to 30-60 fps when double buffering. Also, the delay from triple buffering is one frame, so at 60 fps that's 1/60th of a second, or .017s.


IMO vsynch & triple buffering is usually the way to go.
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by SteelWill /forum/post/15556195


Having vsynch disabled means you're rendering as fast you can, and image tearing usually results because your display ends up showing partial frames. You're also generating more heat and using more juice since your hardware is always pumping out as many frames as it possibly can.


Enabling vsynch will cause your framerate to be capped at your refresh rate.


Then one of two things will also happen with vsynch enabled:


1. Double buffering is used. This means no increased lag but your framerate is always a multiple of your refresh rate. Fore example, at a 60 Hz refresh rate, your framerate will drop to 30 fps if it can't sustain 60 fps, then 15 fps if it can't sustain 30 fps, etc. There is no in between and the sudden large changes in fps can result in things being a bit "stuttery" if it happens frequently.


2. Triple buffering is used. This will result in a slight input delay (you are one extra frame "behind") but your framerate is not limited to multiples of your refresh rate. Your framerate can fall anywhere below your refresh rate and fps fluctuations will be far smoother. For example, if your rig can turn a solid 55-60 fps, that's exactly what will be displayed, as opposed to 30-60 fps when double buffering. Also, the delay from triple buffering is one frame, so at 60 fps that's 1/60th of a second, or .017s.


IMO vsynch & triple buffering is usually the way to go.

Ok, that sounds good. I figured if there was any delay, from the loss of peak/extra frames, it would be quite a bit less than even a second. When I enabled the sync, my fps (reported by xfire) were in the 58-63 range and my monitor is a 60hz plasma. So it seems it is using the Triple Buffer method?
 

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Well that was very informative, being a newbie to PC gaming, it helps researching and finding advice on what settings will perferm the best.


I used to own an X-box 360, I played Ghost Recon for the first time on it and it blew me away graphics wise, only problem was frame rates where under 30fps when character was still and probably dropped under that when engaging in combat, basically there was a ton of ghosting caused by the poor framerates, when there was alot of movement, and made the game virtually unplayable trying to focus after it blurred etc...I ditched it and am in the process of putting together a HTPC for gaming...I expect better results and more mature games than what X-box has to offer.
 

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Quote:
Originally Posted by Blacklac /forum/post/15556341


Ok, that sounds good. I figured if there was any delay, from the loss of peak/extra frames, it would be quite a bit less than even a second. When I enabled the sync, my fps (reported by xfire) were in the 58-63 range and my monitor is a 60hz plasma. So it seems it is using the Triple Buffer method?

Looks like it if that's a real-time reading. There are various ways to force triple buffering if it's not used by default. Sometimes there's an option in game, there's usually one in your video card's control panel (for OpenGL anyway), or you can use D3D Overrider that's available with Rivatuner for stubborn DirectX games.
 

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If you are using V-Sync (which has always been my preference) then it doesn't matter what type of frame buffer technique is being used prior to rendering to the screen.


If your computer/video card cannot maintain 60fps then it is like missing a bus that arrives on the hour, every hour. You have to catch the next one, hence you have effectively dropped to 30fps. This is true even if your system is capable of 59fps. arriving 1 minute late is just as bad as arriving 59 minutes late. Again with the Bus analogy, if you are faster than 60fps it just means you have got to the Bus stop early, and must wait around until it arrives, doing nothing very useful (although multitasking and extra frame buffers means you can make good use of the idle time, the fact is you are not going to render the next screen to the output display until the Bus arrives)


If you are very very slow, and miss not only the first Bus, but the second Bus as well (and thus ruinning at 15fps) then V-sync on or off is not really the big question anymore: It means you need to dial down the graphic settings because they are set too high for your system to cope with.


If on the other hand your system is almost hitting 60fps but not quite (meaning with Vsync you are now at 30fps -or perhaps jumping between 60 and 30 depending on how much action is going on) then this is the strongest case for switching Vsync off -but you are definitely going to get plenty of tearing, assuming your monitor is running at 60fps. Which raises another point. Even if you have Vsync switched off, your display is still refreshing at a consistent rate (eg 60hz). So If FRAPS is telling you that you are getting 176fps, all it means is that there are a lot of screens being rendered to the internal video card buffer that you never even get to see. Further more, tearing happens regardless of speed. Tearing is an issue of synchronisation, not performance.


ps. I have some historical real world background on this. I did a lot of real-time graphics programming in the early days when DOS was still king. Back then, direct access to video hardware registers and memory was standard practice for games programmers. One of the most well known registers (and I guess still used today, only indirectly) was the Vertical Blank indicator, which toggled between 0 and 1. when it was switched on, you were safe to write the current frame directly to Video Memory, knowing that you had enough time to finish the job prior to it being displayed on screen. Ignoring this register meant you risked some of the new frame being displayed with some of the old frame -otherwise termed as tearing.


pps. Tearing still happens during fairly static moments (eg when you aren't panning the display across a room or landscape) but you simply aren't going to notice the fact that part of an old screen and new screen are being displayed. It is just more obvious when their is a lot of temporal activity going on.
 

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Quote:
Originally Posted by Blacklac /forum/post/15554439


All I meant by "reduce speed/response" is introduce minor lag that wouldn't be there otherwise. It seems like it would, but I don't know. I wondered if anyone had hard facts about it.

Yeah, many years of hardcore PC gaming with a mouse has taught me the simple lesson that v-sync sucks. Yes you do lose response as you can spin around much faster than 60fps can keep up.
 

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So tripple buffering is the most usefull to get custom framerates in real time instead of missing the bus at 60 and only getting 30 or 15?


Basically if you *(miss the bus @ 60 with triple buffering ~ you still get 59? Correct?


Is this how most games setting should be set at?
 
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