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Frame Rating: Visual Effects of Vsync on Gaming Animation

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Manufacturer: PC Perspective

Not a simple answer

After publishing the Frame Rating Part 3 story, I started to see quite a bit of feedback from readers and other enthusiasts with many requests for information about Vsync and how it might affect the results we are seeing here.  Vertical Sync is the fix for screen tearing, a common artifact seen in gaming (and other mediums) when the frame rendering rate doesn’t match the display’s refresh rate.  Enabling Vsync will force the rendering engine to only display and switch frames in the buffer to match the vertical refresh rate of the monitor or a divisor of it.  So a 60 Hz monitor could only display frames at 16ms (60 FPS), 33ms (30 FPS), 50ms (20 FPS), and so on.

Many early readers hypothesized that simply enabling Vsync would fix the stutter and runt issues that Frame Rating was bringing to light.  In fact, AMD was a proponent of this fix, as many conversations we have had with the GPU giant trailed into the direction of Vsync as answer to their multi-GPU issues. 

In our continuing research on graphics performance, part of our Frame Rating story line, I recently spent many hours playing games on different hardware configurations and different levels of Vertical Sync.  After this time testing, I am comfortable in saying that I do not think that simply enabling Vsync on platforms that exhibit a large number of runt frames fixes the issue.  It may prevent runts, but it does not actually produce a completely smooth animation. 

To be 100% clear - the issues with Vsync and animation smoothness are not limited to AMD graphics cards or even multi-GPU configurations.  The situations we are demonstrating here present themselves equally on AMD and NVIDIA platforms and with single or dual card configurations, as long as all other parameters are met.  Our goal today is only to compare a typical Vsync situation from either vendor to a reference result at 60 FPS and at 30 FPS; not to compare AMD against NVIDIA!!

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In our initial research with Frame Rating, I presented this graph on the page discussing Vsync.  At the time, I left this note with the image:

The single card and SLI configurations without Vsync disabled look just like they did on previous pages but the graph for GTX 680 SLI with Vsync on is very different.  Frame times are only switching back and forth between 16 ms and 33 ms, 60 and 30 instantaneous FPS due to the restrictions of Vsync.  What might not be obvious at first is that the constant shifting back and forth between these two rates (two refresh cycles with one frame, one refresh cycle with one frame) can actually cause more stuttering and animation inconsistencies than would otherwise appear.

Even though I had tested this out and could literally SEE that animation inconsistency I didn't yet have a way to try and demonstrate it to our readers, but today I think we do.

The plan for today's article is going to be simple.  I am going to present a set of three videos to you that show side by side runs from different configuration options and tell you what I think we are seeing in each result.  Then on another page, I'm going to show you three more videos and see if you can pinpoint the problems on your own.

Continue reading our article on the effects of Vsync on gaming animation smoothness!!

 

Battlefield 3 - 2560x1440 - Ultra Settings

Our first video comparison will look at two fixed frame rate runs of a portion of Battlefield 3, one at 60 FPS consistently and one at 30 FPS consistently.  The first question I'll want to address is on the hardware behind these "reference" runs.  While I will tell you we used Titan cards in SLI for our recordings, the truth it matters very little which configuration we used to get these results, as the goal was to have so much additional performance that we didn't ever worry about frame rates falling below the Vsync rates.  By enabling standard Vsync we were able to capture a steady 60 FPS result and with NVIDIA's half-refresh rate Adaptive Vsync I could capture a solid 30 FPS result. 

Download the 250MB MP4 from Mega.co.nz

Reports from most users are telling us that you NEED to download these files for a solid comparison!

Battlefield 3 - 60 FPS vs 30 FPS Comparison

You should be able to tell pretty easily that the left hand side of this video is the 60 FPS version and the right hand side is the 30 FPS version.  The animation on the left is clearly smoother though neither has any "stutter" or variance in the frame rate.  Yes, the right side won't look as good in comparison, but when viewed on its own (cover the left side with a piece of paper) and it should look great in real time and lower speeds.

In data form, this is what this comparison looks like:

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The black line is nearly completely static at 16 ms frame times (only a single frame time spike to the higher 33 ms rate) resulting in a completely smooth 60 FPS animation rate on the screen.  Our orange line shows the result of Adaptive half-refresh rate settings from NVIDIA's control panel giving us a static 30 FPS (33 ms) animation rate, with one instance of higher / lower frame times. 

 

Our second video will now bring in a typical graphics card configuration with standard Vsync enabled and compare it to the 60 FPS result above.  In this case the test is using a single Radeon HD 7970 GHz Edition card but again this could be any card, in any game at any settings that has frame rates under the maximum refresh rate of your display for significant amounts of time.

Download the 250MB MP4 from Mega.co.nz

Reports from most users are telling us that you NEED to download these files for a solid comparison!

Battlefield 3 - 60 FPS vs Standard Vsync Comparison

In this video, the 60 FPS result is on the left and the HD 7970 running standard Vsync is on the right hand side.  You should be able to see at real time the difference in smoothness between these two different user experiences and it will be more apparent when we slow down the video to 50% and 20%. 

What does this look like in data form?

View Full Size

The black line is our 60 FPS static reference video while the orange line represents the standard Vsync run with the Radeon HD 7970 card.  What kind of appears as "blocks" of orange on the graph is actually very quick and repeated variation in the instantaneous frame rate of 16 ms and 33 ms. This is due to the the function of Vsync that forces the frame to only be displayed at each refresh cycle of the display.  In the first 20 seconds of the game, Battlefield 3 with these settings and this hardware is switching between 60 FPS and 30 FPS pretty regularl,y and because of that you see the differences in animation smoothness above. 

 

What is maybe most interesting is our final video that compares a flat 30 FPS to the same Vsync result shown above.

Download the 250MB MP4 from Mega.co.nz

Reports from most users are telling us that you NEED to download these files for a solid comparison!

Battlefield 3 - 30 FPS vs Standard Vsync Comparison

The left hand side is the static 30 FPS result and on the right again is the Vsync run from the Radeon HD 7970 GHz Edition. Comparing the video in this case is much more interesting as in my experience there are some divided opinions.  In a purely mathematical view the screen on the left should be "smoother" than the animation on the right hand side, even though on average it is running at a lower frame rate per second.  However, the Vsync result has variance in frame times and thus you can see some patterns to the frames that don't exist at static 30 FPS or 60 FPS results.  It kind of halts, or appears to freeze some times as a result of seeing frames at 16 ms, 16 ms, 16 ms, 33 ms, 16 ms, 16 ms...

Maybe looking at the data will help describe the phenomenon.

View Full Size

Clearly the black line of frame times is the same or slower than every instance of the orange line that represents the Vsync video output.  However, the black line is consistently at 30 FPS while the orange line varies between 30 FPS and 60 FPS.  Those periods of 60 FPS visuals are definitely smoother than the 30 FPS result (as we showed you in the first video on this page) but the variance in frame rates is actually more noticeable than you might have otherwise realized.

Despite all the arguing back and forth on what the limit of frame rate perception of the human eye is, there is one thing that is true without doubt - the human eye and brain can detect very subtle changes in animations pretty easily.  Looking at a five second animation at 55 FPS and then 60 FPS, you'd be hard pressed to tell which is which.  But if you see a video running at 60 FPS that suddenly drops to 30 FPS and you can clearly see the effect. 

Now comes the real debate - which side of the video above is better?  "Better" is a term that has many meanings and I don't have any doubts that there will be variance in answers from our readers across the world.  I fall on the side of more static frame rate - consistent 30 FPS performance is better than what we have in many cases with traditional Vsync.

 

Now, on the next page, we are going to present the same videos and data but without telling you which result is which.

April 16, 2013 | 03:59 PM - Posted by corhen (not verified)

we see all these comments about Vsync, but how does nvidias "adaptive vsync" fare?

April 16, 2013 | 10:51 PM - Posted by svnowviwvn

I would also like to see an analysis of Nvidia's "adaptive vsync"

April 16, 2013 | 11:43 PM - Posted by Ryan Shrout

Fair enough, we just wanted to show you a vendor agnostic comparison on Vsync at first.

April 18, 2013 | 06:20 PM - Posted by Anonymous (not verified)

While you have your Request Book open what about:

Virtual VSync
http://www.lucidlogix.com/technology-virtual-v-sync.html

A quote from that Page: "Virtual Vsync enables games to run at any FPS, with no image tearing, stuttering, lags and latency artifacts." .

Can you tell us if it does indeed 'fix everything' -- If it does you can use it as the Base System.

Thanks for these Articles and working on this for us.

April 26, 2013 | 09:10 AM - Posted by endiZ (not verified)

nVidia's Adaptive sync vs RadeonPro Dynamic sync control comparison would be great!

http://www.radeonpro.info/features/dynamic-vsync-control/

April 16, 2013 | 04:12 PM - Posted by Martin (not verified)

Was the conclusion that with a sufficiently fast card that consistently gives frame times less than 16 ms, Vsync will always give a smoother animation at the cost of up to 16 ms extra input lag?

April 20, 2013 | 07:38 AM - Posted by Bogdan (not verified)

My sentiments exactly! Obviously, even with no direct comparison between the two giant GPU manufacturers, there's no doubt in my mind that Adaptive VSync really "brings the best of both worlds" in terms of smooth transitions between various frame times while under the 60FPS barrier. Even at constant 60 FPS I could live with extra 16ms input latency even on more demanding games in this respect (like maybe Dirt 3), provided I get state of the art image quality.
Also, bare in mind that when I turn on VSync in Crysis 3 menu on my GTX690, it is for sure Adaptive VSync that's at work, and not standard VSync. That is with default settings in NVidia Control Panel! So no worries there on the NVidia side...
Thank you Ryan for your dedication and professionalism in bringing us all these really fine reviews! You guys are doing a great job there, and most impressive it's out of real passion.
Keep it up! Sky is the limit! :-)

April 16, 2013 | 04:37 PM - Posted by ezjohny

The left side was clearly the winner here.
Your way of testing certain portion of the game is very educational to the public, thank you for this!

April 16, 2013 | 09:57 PM - Posted by Anonymous (not verified)

The winner of what?

He's got what seems like an SLI setup that can sustain 60 fps with vsync on compared to a half the price non-crossfire setup with vsync on to create inconsistency.

April 16, 2013 | 11:44 PM - Posted by Ryan Shrout

The goal of these vidoes was NOT to compare SLI vs a single card.  The goal was compare what you can see at 60 FPS fixed against ANY Vsync situation and 30 FPS against ANY Vsync situation.  

Reading comprehension!

April 17, 2013 | 02:12 AM - Posted by Anonymous (not verified)

That you for editing your article to help make clear what you stated above.

Maybe edit this as well?

"What does this really mean based on our previous Frame Rating data sets, AMD's CrossFire issues and user experiences?"

It means absolutely nothing since non-crossfire doesn't have issues without Vsync.

"In fact, AMD was a proponent of this fix, as many conversations we have had with the GPU giant trailed into the direction of Vsync as answer to their multi-GPU issues. "

Reading comprehension!

April 17, 2013 | 07:23 AM - Posted by JCCIII

That was my conclusion, too. The videos were so well done that I made my choices within seconds of each. The sign “Recycling Limited Company” was irregular on the right.

And, the truth comes: am I a videophile or a poser; I sure hope I will sleep tonight!

Joseph C. Carbone III

April 16, 2013 | 04:48 PM - Posted by Paul Keeble (not verified)

It took me a maximum of 5 seconds in every case to identify those. Identifying them was immediately obvious, I did not need the 50% or the 20% slow down to be able to tell the difference. You could have done that test with considerably smaller files.

April 16, 2013 | 09:58 PM - Posted by Anonymous (not verified)

Are we able to identify what the 7970 was being compared to exactly?

April 17, 2013 | 10:18 AM - Posted by bystander (not verified)

The 7970 wasn't the comparison. The comparison was the difference between a fixed 30 FPS or fixed 60 FPS compared to v-sync on when there is variation between the two.

April 16, 2013 | 05:10 PM - Posted by Bryan Watson (not verified)

Just a tip for recording these demonstration videos in the future:

I found myself more distracted on the actual time difference between actions on the video then the smoothness of the animation.

You can get much better comparison videos by running a keyboard / mouse macro to replicate the exactly same keypresses and mouse movements every time.

That way you would have near identical videos that you could sync easily and provide a much clearer ground for comparison.

April 16, 2013 | 07:02 PM - Posted by Ryan Shrout

Thanks for the tip but we have tried that before and macro programs don't respond to input for games consistently...

April 17, 2013 | 12:39 AM - Posted by Steve W. (not verified)

Hey Ryan,

I would like to propose adding a canned benchmark to the mix. They might not be ideal for real world Benchmark between cards, but I think they should do fine in judging smoothness. Either in split copy or half and half or both =).

My picks for canned benchmark:

-Batman - Arkham City ( This benchmark has good amount of panning especially that "hiccup" in the beginning when panning up the stairs, and bunch of fast shooting objects although done by physx).

-AVP (lots of up close and large moving "beings")

-Lost Planet 2 Benchmark (the one with 3rd person in-game play, and closest to what the previous poster Bryan Watson suggest)

-Catzilla (non-real game but uses newer capabilities (OpenGL 4.0 and DirectX 9/11... and faster pace as oppsed to heaven, and just plain cooler)

-there are probably better ones, but these are the ones I've played around with on my 680.

Other thoughts... The 60fps vs Vsync difference is very unnoticeable, but jumping to a possible next level of testing is mouse/keyboard lag comparison (you mentioned it somewhere but I can't remember) which in my opinion is icing on the cake. (maybe that could lead to debunking "gaming" keyboard and mice vs ps2,standard or even wireless! very destructive info imho)

ps. the music needs more wub wub

April 16, 2013 | 08:56 PM - Posted by Humanitarian

This was distracting me a little too, Blocking off half your monitor with card or paper makes it a lot easier.

April 16, 2013 | 06:03 PM - Posted by looniam (not verified)

if i listen to that music anymore i will promptly put a spike through my head.

i know there is a mute but, it takes away from the experience! :p

April 16, 2013 | 07:02 PM - Posted by Ryan Shrout

So, you're saying you need new background music, check.

April 16, 2013 | 08:56 PM - Posted by Humanitarian

Definitely needs more wub wub.

April 16, 2013 | 07:09 PM - Posted by Maester Aemon (not verified)

This time I'm a bit confused with your results. Everybody knows that enabling standard vsync on a game where the GPU can't sustain fps above 60 is a bad idea because even if the fps go down to 59, then the everything is rendered at 30 fps until the GPU can go back to 60 or above.

The real question is, what about the case where a Crossfire configuration is capable to run a game without ever going below 60 fps and then, when you enable vsync the games runs at a constant 60fps with no drops to 30fps at all? Does that solve the runt frames and stuttering issue?

April 16, 2013 | 09:42 PM - Posted by Anonymous (not verified)

Showing this wouldn't be consistent with what the sponsor wants to present.

You have to think of all parties involved.

I'm curious, what was the actual Nvidia setup used in the battlefield 3 comparison? If it's something that can handle 60+ fps without issue, then it's easy to see why this comparison is silly.

April 16, 2013 | 09:53 PM - Posted by Anonymous (not verified)

Reread this...

"And of course, enabling Vsync results in a situation where the frame rate does NOT dip below 60 FPS, as we did with our reference videos used in this article, will not result in animation inconsistencies."

So why not use crossfire 7970 as well? 7970 on it's own doesn't have tearing issues with v-sync off.

April 16, 2013 | 11:47 PM - Posted by Ryan Shrout

You guys and your conspiracies never get tired, do you?  :)

To quote a comment I left above...

"The goal of these vidoes was NOT to compare SLI vs a single card.  The goal was compare what you can see at 60 FPS fixed against ANY Vsync situation and 30 FPS against ANY Vsync situation. 

Reading comprehension!"

April 18, 2013 | 02:11 AM - Posted by techno (not verified)

I know this is a comparison of vsync vs fixed frame rates....but the reason you are doing this is because of the hullabaloo your new methods have caused in relation to crossfire.

The question that was raised was "does vsync address the crossfire issue?"

This article does not address this and merely tries to slur vsync as a possible fix.

We all know vsync has the issues you have high ligthed but please answer the question.

"Does vsync in situations where frame rates are consistently above 60fps fix the crossfire problems?"

You have not answered this and have just tried to slur AMD's response without proper testing.

Ryan your blood runs GREEN.

April 20, 2013 | 09:16 AM - Posted by Bogdan (not verified)

You know what? I think too Ryan's blood runs Green, and to be perfectly honest I wouldn't mind if mine ran the same color, just as long as what's been showed it's from the editorial stance and one's dedication to show us ALL how actual technologies impact on various game experiences.

Even if he hasn't clearly stated (and it is said from the beginning of this article that we're not comparing the two GPU giants), it is my understanding that any GPU configuration powerful enough to consistently run over 60FPS will have no problems delivering smooth gaming experience at 60Hz-60FPS. By all means, that's good news for me and my GTX690, and it'd be the same if I owned a pair of 7970s (JUST for me personally no thanks! - due to greater power consumption, extra space requirements, worse noise and temperature levels inside my CM690 II Advanced case).

I think what Ryan means is to show us ALL (and THAT means not only me or others with ARES II in their cases), just what happens when you have a GTX670, GTX680, a HD7970, or other SLI/CF GPU configurations which don't always stay above 60FPS barrier and what your choices and tradeoffs would be in respect to VSync, image quality and gaming experience.

As for his sponsors, I think that's entirely his problem and doesn't concern us, just as long as what we read, see and hear is pertinent and objectively explained on specific topics. As for what everyone understands, that's another story...

PS: Just to be clear, not taking into consideration the high-end/highly expensive GTX690 and Titan (especially this one!), I think that hardware implemented Adaptive VSync is an obvious step forward from the Green Team, and that is especially valid for those of us who don't necessarily get to buy extreme graphics cards. I can't wait for AMD to pick up the pace and give Nvidia some rough times, but for now please don't mind if "my blood runs green" too!

Thanks again, Ryan - for your dedication and professionalism!

Peace to all! May it be that we fight only on game servers and really nice forums like PC-PER.

April 16, 2013 | 07:15 PM - Posted by AlienAndy (not verified)

Thanks again for your tireless efforts, Ryan.

Really looking forward to seeing some older cards tested.

April 16, 2013 | 08:49 PM - Posted by tbone (not verified)

good comparison but certain sections distracted me from the left vs right like when one scene has motion and the other doesn't like a car or motorbike...for example the motorcycle at the end on the left distracted me from viewing the right.

first video was obvious when at 50%

second video not so clear to me which was better even at 50%, by 20% maybe a little yes.

third video was impossible for me to tell the difference between the 2.

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