Do you need Vsync with a 120Hz Lcd?

zod96

Platinum Member
May 28, 2007
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If you have a 120Hz Lcd do you still need Vsync? And if you use Vsync on a 120Hz lcd does that cap the FPS at 120?
 
Nov 26, 2005
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You do NOT need Vsync enabled.
You may still report more than 120fps from the game...
What you WILL notice is fps minimums more than maximums at that point.
 

Ben90

Platinum Member
Jun 14, 2009
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Vsync is one of those things that you need to decide for yourself. There are benefits and drawbacks to having it both on and off.

The first thing is that no matter what your framerate is, without Vsync, your screen WILL tear. That is something to keep in mind. A common misconception that even I held at one point is that if your FPS are under the refresh rate, Vsync really doesn't do much. This is not true. Even at 1 frame per second, the chance of it tearing is near 100%. The change raises the more vertical pixels you have.

In a perfect implementation, Vsync would be without drawbacks. However I have noticed that in most engines it adds more input delay than the math would imply. I cannot explain this and its not everywhere. I have tried to rule out obvious factors such as disabling rendering ahead but that works only sometimes.

Try it for yourself, if tearing bothers you more than the extra delay than turn it on. If its reversed, take it off. If your truly impartial, I would turn it on for less power consumption.
 

Throckmorton

Lifer
Aug 23, 2007
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Anandtech has an article on frame lag, vsync, etc.

Turning on Vsync when the framerate is below the hz of the monitor adds input lag
 

Idontcare

Elite Member
Oct 10, 1999
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I did not know what tearing was until I decided one time to disable vsync...then I was like OMFG what is wrong with my screen!

I thought maybe a cable had come loose or my GPU was dying. Then I remembered I was playing around with the settings and had disabled vsync.

Re-enabled vsync and the horrid screen atrocities went away. I don't see how people can ignore it and avoid using vsync.
 

bunnyfubbles

Lifer
Sep 3, 2001
12,248
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The beauty of a 120Hz monitor is that the faster refresh rate will reduce input lag (relative to 60Hz) even if you do choose to run with vsync, of which I have found no need to as the other beauty of a 120Hz monitor is that tearing will be far far far less apparent regardless of whether your frame rate is above or below the refresh rate.

I used to be largely immune to screen tearing on a 60Hz LCD, after being spoiled by my 120Hz LCD I almost can't stand it, it just about makes me sick that I have to turn vsync on. The problem then is the input lag goes through the roof relative to my 120Hz LCD and that is just too infuriating to put up with for any kind of competitive game.
 
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tviceman

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Mar 25, 2008
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I did not know what tearing was until I decided one time to disable vsync...then I was like OMFG what is wrong with my screen!

I thought maybe a cable had come loose or my GPU was dying. Then I remembered I was playing around with the settings and had disabled vsync.

Re-enabled vsync and the horrid screen atrocities went away. I don't see how people can ignore it and avoid using vsync.

Yeah I am the exact same way. Whenever I read about the occasional console game that has screen tearing, I cringe at the idea that the direction of our current future path will not allow us to customize graphical settings for games. :/
 

taltamir

Lifer
Mar 21, 2004
13,576
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There is no reason to turn of vsync, EVER! Anyone who tells you to disable it is just ignorant and wrong. This is a personal choice the same way homeopathy is a "personal choice". You get to choose whether to seek real medical care or not... but homeopathy will never "work best for you" no matter what you delude yourself into thinking.

Yes, Vsync is absolutely needed with 120Hz monitors.

And if you use Vsync on a 120Hz lcd does that cap the FPS at 120?
A 120Hz monitor is only physically able to show 120 pictures (frames so to speak) for every unit of t (which is measured in seconds)... aka FPS. Your video card could be rendering eleventy billion frames per second and your monitor will still only show you 120 frames per second. Vsycn synchronizes the frames rendered by your video card to those displayed by your monitor (by matching the monitor's vertical refresh rate), this does limit the FPS your video card generates. But that is a GOOD THING. It saves electricity, it lowers heat generation, increases longevity of your card, reduces noise levels, and provides a smoother better quality visual experience compared to unnecessary and detrimental over rendering out of sync frames.

BTW, I had an issue with capacitor squeal on my video card in the main menu of neverwinter nights... because it was rendering in 3000 FPS. :p Vsync fixed that.

I don't see how people can ignore it and avoid using vsync.

I really don't either... but its not the craziest thing people would do.
 
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lavaheadache

Diamond Member
Jan 28, 2005
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I did not know what tearing was until I decided one time to disable vsync...then I was like OMFG what is wrong with my screen!

I thought maybe a cable had come loose or my GPU was dying. Then I remembered I was playing around with the settings and had disabled vsync.

Re-enabled vsync and the horrid screen atrocities went away. I don't see how people can ignore it and avoid using vsync.

Ditto
 

bunnyfubbles

Lifer
Sep 3, 2001
12,248
3
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There is no reason to turn of vsync, EVER!
Input lag and massive frame rate drop when the video card can't keep up with the refresh rate are two reasons, not none. There are other issues such as increased memory requirement (particularly with triple buffering) or simple game timing issues that can be messed up with vsync, but these are minor relative to the first two points.

Anyone who tells you to disable it is just ignorant and wrong.
Irony.jpg


This is a personal choice the same way homeopathy is a "personal choice". You get to choose whether to seek real medical care or not... but homeopathy will never "work best for you" no matter what you delude yourself into thinking.
2891560590_15903c3f05_o.jpg


Of course in your case your analogy is just completely wrong to begin with.


Yes, Vsync is absolutely needed with 120Hz monitors.
Do you even use a 120Hz monitor?


A 120Hz monitor is only physically able to show 120 pictures (frames so to speak) for every unit of t (which is measured in seconds)... aka FPS. Your video card could be rendering eleventy billion frames per second and your monitor will still only show you 120 frames per second. Vsycn synchronizes the frames rendered by your video card to those displayed by your monitor (by matching the monitor's vertical refresh rate), this does limit the FPS your video card generates. But that is a GOOD THING. It saves electricity, it lowers heat generation, increases longevity of your card, reduces noise levels, and provides a smoother better quality visual experience compared to unnecessary and detrimental over rendering out of sync frames.

BTW, I had an issue with capacitor squeal on my video card in the main menu of neverwinter nights... because it was rendering in 3000 FPS. :p Vsync fixed that.
You just described double buffered vsync, which is by far the worst kind as it incurs the greatest input lag and neutered GPU performance if the GPU can't keep up with the refresh rate.

Triple buffering would solve this but most "triple buffering" options aren't true triple buffering (and what we have instead is frame queue flipping) and in either case the video card is working nearly as hard (but potentially using quite a bit more memory) relative to vsync off, so that advantage goes out the window.

True vsync triple buffering support is extremely rare, is only officially force-able for OpenGL based games, requires a hack to to even think about running for D3D games, and is also incompatible with every method of SLI/Crossfire except for split frame rendering (far from ideal) and thus isn't even an option for some of us.


I really don't either... but its not the craziest thing people would do.
It's quite simple really: people who play competitive video games - and are also actually very good at said games - turn vsync on and they immediately feel like their movements are rubber banding all over the place and thus naturally find it hindering their performance, so they quickly turn that crap off and put up with the potential screen tearing instead.



To summarize:

1. the option of Vsync is personal opinion - some people can't put up with tearing and thus prefer vsync on, while some people can't put up with input lag and thus prefer vsync off.

2. type of game can greatly influence use of vsync. Games that are far more demanding of fast reflex reactions are going to favor vsync off while casual games or games that favor more of a macro user input and are less demanding of micro input will be more compatible with having on vsync on.

3. stressfulness of a game can also come into play as well - games that are extremely GPU intensive will likely not need vsync or actually be greatly hindered by having it on, while older games that simply run no lower than a couple hundred fps even with anti aliasing cranked all the away could benefit greatly from having vsync on.
 

Dankk

Diamond Member
Jul 7, 2008
5,558
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Thank you for that, bunnyfubbles.

There is no reason to turn of vsync, EVER! Anyone who tells you to disable it is just ignorant and wrong.

Yeah... sorry dude. Please make a better effort to understand what you're talking about before making a point about it. Vsync can, in fact, have detrimental effects on gameplay, usually in the form of input lag. It's not always noticeable, but it's there. Some game engines handle Vsync absolutely horribly. Other than that, for singleplayer games it's fine; but for multiplayer games I choose to disable Vsync to eliminate input lag. Input lag can be the difference between killing an enemy, or getting yourself killed. Again, not very common, but it's possible.
 

snuuggles

Member
Nov 2, 2010
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Hey, sorry if I'm not 100% getting it. I plan on upgrading from a 60hz to 120hz monitor soon. My hope was that it would allow vsync on *and* better/same input lag. It seems like the consensus is that vsync is just going to cause problems almost no matter what, unless your frame rate is above the refresh rate of the display?!?

Does that mean that upgrading to 120hz causes *more* input lag given the same gpu? Since now there is a higher ceiling before you exceed the displays refresh rate?

Sorry this issue wasn't even on my radar, I just assumed 120hz input was better in every circumstance given the same hardware otherwise

I'm very sensitive to input lag, so I would obviously just continue to leave vsync off but it's pretty disappointing if it's *worse* on the new technology.
 

Emulex

Diamond Member
Jan 28, 2001
9,759
1
71
dude unless its hdmi 1.4 you can't send more than 1920x1200 (using an example of 24" typical 16:10) in a 60hz period. if you have hdmi 1.4 you can send two frames in the same period (somewhat similar to 120hz mode). this is how 3D is done proper on the Geforce 430 hdmi 1.4 expands the resolution of the hdmi greatly. go check out the specs to see what matches you. but if your card can't crap @ 120hz then digitally and most cards can't - then you are screwed. analog - that's another story
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
http://www.anandtech.com/show/2794/2

In other words, with triple buffering we get the same high actual performance and similar decreased input lag of a vsync disabled setup while achieving the visual quality and smoothness of leaving vsync enabled.

The issue would be whether or not you enable triple buffering for your vsync.

Cute witty pictures or saying "Please make a better effort to understand what you're talking about before making a point about it" don't make your argument any less wrong.
 
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imaheadcase

Diamond Member
May 9, 2005
3,850
7
76
I've ALWAYS disabled vsync and never had any tearing. I don't see any reason to enable it for that matter.
 

ArchAngel777

Diamond Member
Dec 24, 2000
5,223
61
91
Triple buffering would solve this but most "triple buffering" options aren't true triple buffering (and what we have instead is frame queue flipping) and in either case the video card is working nearly as hard (but potentially using quite a bit more memory) relative to vsync off, so that advantage goes out the window.

This does not line up with my own testing and a Kilo-Watt meter. Every game I tested (5) used far less power from the wall when Vsync was enabled. The most notable was Lost Planet. In the case of a 60Hz monitor and you are often seeing 100 FPS spikes, it will save a lot of power and keeps the GPU and CPU temps down.

In the case of 120Hz, I would leave Vsync off, unless there was an older game that had me exceeding the 120 FPS on a regular basis.
 

bryanW1995

Lifer
May 22, 2007
11,144
32
91
There is no reason to turn of vsync, EVER! Anyone who tells you to disable it is just ignorant and wrong. This is a personal choice the same way homeopathy is a "personal choice". You get to choose whether to seek real medical care or not... but homeopathy will never "work best for you" no matter what you delude yourself into thinking.

Yes, Vsync is absolutely needed with 120Hz monitors.


A 120Hz monitor is only physically able to show 120 pictures (frames so to speak) for every unit of t (which is measured in seconds)... aka FPS. Your video card could be rendering eleventy billion frames per second and your monitor will still only show you 120 frames per second. Vsycn synchronizes the frames rendered by your video card to those displayed by your monitor (by matching the monitor's vertical refresh rate), this does limit the FPS your video card generates. But that is a GOOD THING. It saves electricity, it lowers heat generation, increases longevity of your card, reduces noise levels, and provides a smoother better quality visual experience compared to unnecessary and detrimental over rendering out of sync frames.

BTW, I had an issue with capacitor squeal on my video card in the main menu of neverwinter nights... because it was rendering in 3000 FPS. :p Vsync fixed that.



I really don't either... but its not the craziest thing people would do.

ah yes, the beloved capacitor squeal at the start of nwn2...those were the days...
 

ArchAngel777

Diamond Member
Dec 24, 2000
5,223
61
91
ah yes, the beloved capacitor squeal at the start of nwn2...those were the days...

Yeah, the squeal at the menus in certain games can be really bad. However, that is not enough reason to turn it on. You shouldn't be at the game menu long :D

But, I run 60Hz and have a fairly powerful video card for my resolution 1050P, so I leave Vsync on and enabled TB. Whether it is true TB or Queue Flipping, I couldn't care less because the power consumption drops considerably.

But, make no mistake, just because I could not care less doesn't mean others cannot. If I was a competitive gamer, I'd probably have a different view and look at Vsync as the devil. To each their own... I personally hate tearing, and before I upgrade to a 120Hz monitor, I need to make sure it is an IPS panel. So until I purchase a 120Hz monitor, Vsync will remain a staple.

This is one of those debates that ends up the same as CRT Versus LCD. Each person has their preference. There is a pro and con for both. Just be glad we have these options, unlike a console... :p
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
Yeah, the squeal at the menus in certain games can be really bad. However, that is not enough reason to turn it on. You shouldn't be at the game menu long :D

I never said it was the reason you should turn it off. I explained in detail why. I have yet to see a legitimate argument for turning vsync off though.

Even a competitive gamer should use vsync. The whole input lag claims for vsync are utter FUD.
 

bunnyfubbles

Lifer
Sep 3, 2001
12,248
3
0
Hey, sorry if I'm not 100% getting it. I plan on upgrading from a 60hz to 120hz monitor soon. My hope was that it would allow vsync on *and* better/same input lag. It seems like the consensus is that vsync is just going to cause problems almost no matter what, unless your frame rate is above the refresh rate of the display?!?

Does that mean that upgrading to 120hz causes *more* input lag given the same gpu? Since now there is a higher ceiling before you exceed the displays refresh rate?

Sorry this issue wasn't even on my radar, I just assumed 120hz input was better in every circumstance given the same hardware otherwise

I'm very sensitive to input lag, so I would obviously just continue to leave vsync off but it's pretty disappointing if it's *worse* on the new technology.

No, assuming the computer the 120Hz monitor is attached to isn't a complete bottleneck and can actually feed the monitor over 100fps on average a 120Hz LCD will be less impacted by tearing regardless of vsync being off and less impacted by input lag if you choose to have vsync on. Its a win-win. That being said, I have almost always left vsync off regardless of 60 or 120Hz.

dude unless its hdmi 1.4 you can't send more than 1920x1200 (using an example of 24" typical 16:10) in a 60hz period. if you have hdmi 1.4 you can send two frames in the same period (somewhat similar to 120hz mode). this is how 3D is done proper on the Geforce 430 hdmi 1.4 expands the resolution of the hdmi greatly. go check out the specs to see what matches you. but if your card can't crap @ 120hz then digitally and most cards can't - then you are screwed. analog - that's another story

I'm not sure exactly what you're trying to say, but the newest Display Port has enough bandwidth to do 2560x1600x30bit @ 120Hz, and dual link DVI can do 1080p 120Hz (this is exactly what is done with my primary monitor), something HDMI cannot do. HDMI can do 3D video because most video is only 24-30fps so no more bandwidth than 1080p60 is needed even if you're doubling up the images.

For a video card to drive 1080p 120Hz all it needs is a dual link DVI which is extremely common for modern cards to have, especially cards powerful enough to drive 3D PC games.

http://www.anandtech.com/show/2794/2

The issue would be whether or not you enable triple buffering for your vsync.

Cute witty pictures or saying "Please make a better effort to understand what you're talking about before making a point about it" don't make your argument any less wrong.

You completely failed to read anything I wrote (especially about triple buffering) didn't you.

This does not line up with my own testing and a Kilo-Watt meter. Every game I tested (5) used far less power from the wall when Vsync was enabled. The most notable was Lost Planet. In the case of a 60Hz monitor and you are often seeing 100 FPS spikes, it will save a lot of power and keeps the GPU and CPU temps down.

In the case of 120Hz, I would leave Vsync off, unless there was an older game that had me exceeding the 120 FPS on a regular basis.

Were you running vsync with triple buffering (whether real or queue flipping?) and comparing it during these tests? Triple buffering should clearly consume more power than double buffering, which was my point at that part.

Even a competitive gamer should use vsync. The whole input lag claims for vsync are utter FUD.
You are obviously not a competitive gamer, or are at least not a very good one.
 

lavaheadache

Diamond Member
Jan 28, 2005
6,893
14
81
blah, blah , blah.. Bickering about who must be terrible competetive gamer....? come on guys, bored are we?



Tearing looks like anus. This is why I use vsync. I don't understand people who can't play with anything less than 4xaa complaining about jaggies but don't mind when images virtually tear in half up and down the screen.

Now, the flip side.... I can and do notice the input lag associated with vsync and even more so triple buffered but that is definatley the lesser of the evils IMO