Does Antialiasing / Transparency create input lag?

Discussion in 'Videocards - NVIDIA GeForce Drivers Section' started by Fabulist, Jan 6, 2014.

  1. scandrew

    scandrew Guest

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    Fabulist, have you researched this matter further? I have the similar issue. I read through all of these comments and it seems either people on this forum are not knowledgeable enough on this particular matter, or our equipment produces different results and therefore others do not experience it as we do. I definitely see the difference in smoothness while turning the AA off at the SAME FPS.

    For example in Tomb raider while standing still and just panning around (moving the mouse left and right), I get around 30 FPS with FXAA ON. Same 30 FPS (FRAPS) with it OFF. With anti aliasing off, while panning, it definitely looks much smoother, even though the FPS are the same. So what is causing this?? This is some kind of stuttering I assume.
    I also noticed this in Crysis 3, and I believe in every other game. These two were the latest I tested and definitely can say that the difference is apparent.

    I use a Single GPU AMD 280X with eyefinity 3 x 27" (1920x1080) screens.
    I am also looking for an explanation.
     
  2. yasamoka

    yasamoka Ancient Guru

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    FXAA is post-process AA, barely requiring any GPU power. 30FPS is a bad target to look for differences in input lag at, anyways. And stutter is a different scenario altogether.
     
  3. Shadowdane

    Shadowdane Maha Guru

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    A better way to check this would be using the benchmark mode in FRAPS and select the "Frametime" option. That will output a .csv file of how long each frame took to render. The lower the values the less apparent input lag you'll have.

    If you cap your framerate or use VSync you'd want as close as possible to whatever your fps rate is. So if your aiming for 30fps you'd want all your frametimes values at 33.3333ms. If you have a lot of deviations from that you'll see stutters.

    144hz/144fps = 6.9444ms
    120hz/120fps = 8.3333ms
    75hz/75fps = 13.3333ms
    60hz/60fps = 16.6667ms
    30hz/30fps = 33.3333ms
     
  4. Guy.J.

    Guy.J. Guest

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    This.
     

  5. LuckyNumber8

    LuckyNumber8 Guest

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    I have read about MSAA lag theory 2 years ago. First I didnt belive that but I run some responsive games (ut 99, and ut 2003). Both games were caped @60 fps, and without MSAA my game experience was perfect. But as soon as I turned on MSAAx4 in Nv CP, mouse movement became slugish in both of this games, it was much harder to aim.

    I dont know if it's just Nv drivers issue, or MSAA issue, but now I can feel that lag in all games, and for me it's a fact.

    http://hardforum.com/showpost.php?p=1040218375&postcount=8
    I agree with his observations
     
    Last edited: Aug 10, 2014
  6. ESlik

    ESlik Guest

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    I have a fairly high end rig too,and I think it was a very good question.
     
  7. Fabulist

    Fabulist Member

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    I agree as well. It has been some time since I created this thread and I have been playing CSGO / BF4 for quite awhile now. I do believe that antialiasing does in fact introduce input lag even if absolutely nothing changes on your framerate. However, beyond my own "senses" I have no proof whatsoever and neither does "readeh" unfortunately. Additionally, this could be an engine based issue rather than a global one. For example; Frostbite / Source engines will always suffer from input lag when some form of antialiasing is active, while other engines will not suffer from input lag.

    So far, every topic regarding this issue has been only opinion based, and although some are very constructive and elaborate, they are still lacking the fundamental tests necessary to reach a less biased conclusion or even a factual result.

    I believe that if there is anyone who can determine this is the people over at Blurbusters, they seem to be the only ones that have the necessary equipment to make such tests and are sharing their results in public.
     
  8. MrBonk

    MrBonk Guest

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    The only latency can possibly be from frame rate and frametime issues. (And if you downsample and use a mouse as well)

    I've played tons of games with all kinds of crazy AA on several different monitors/TV without any induced latency from AA>
     
  9. mubaidr

    mubaidr Guest

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    As long as your GPU is able to handle graphics well, it does not create any lag.
     
  10. bishi

    bishi Master Guru

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    What you are feeling as lag is probably even though your framerate is good most of the time when you are watching it, it drops quicker in action because of the extra overhead of the antialiasing etc in combat/hectic scenes. I still do not believe that anti-aliasing, providing you have spare GPU overhead, will create any input lag.

    The various forms of antialiasing around and different game engines that implement antialiasing in their own ways would make this tough to test efficiently
     

  11. tsunami231

    tsunami231 Ancient Guru

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    Suprised this is still being debated, ANYTHING that modify the ORIGINAL image to add effect of any kinds is adding Latency to cause more time is needed plain and simple. Weather one notices it is dependent on the invdivual.

    For same reason some people that use Vsync dont notice latency vs no vsync and some do. Some engine act worse some act better. it all up to the individual. general speaking if your 60FPS or 120FPS with and with out AA you wont notice it if for the most part unless you pick up on these things which is again individual thing
     
  12. hearnia_2K

    hearnia_2K Active Member

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    Input lag is the period of time from a frame entering the monitor through the DP/DVI/HDMI port to the time when it is displayed on the LCD panel.

    The content of that frame will not affect input lag, it is the processing time by the panel driver board to build and send the correct signal to the LCD panel; hence it is the lag between the input and output of the monitor.

    In this period of time we decrypt any HDCP protected signal, analyze that frame from the transport protocol and prepare it for the LCD panel.

    Again, this period of time will not be affected by in-game settings.

    There may be 'frame lag' perhaps, but that is entirely different, just displaying (sort of) similar results. This

    You can compare input lag by mirroring displays (ideally with an external device) to a high-end CRT and the LCD to compare, and displaying a large clock showing milliseconds. Then take a photo of it, and the times displayed will be very different.

    For me I notice this when using my dual LCD setup - if I move a window which is halfway on both LCDs then I see on one the window is moving very slightly behind the other side, as the input lag is significantly longer on my Dell 2407 A00 monitor.

    So, ultimately the answer to the question is simply, no. AA cannot affect input lag - this is a fixed component of your LCD monitor.

    RealNC explains nicely how frame lag could well give a similar symptom, however:

     
    Last edited: Aug 11, 2014
  13. LuckyNumber8

    LuckyNumber8 Guest

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    I dont know if it's "input lag" in technical terminology. What I know for sure is, when I add MSAA in NV cp, mouse movements (in games like ut1 and ut2033, end even crysis 1) arent that responsive anymore (and there's still the same 60 fps cap). So in my opinion, these guys who wrote about "MSAA lag" are telling the truth, because that's also my experience. I dont know why that happens, but for me the difference in mouse movements is so big, that I will nevel call that ilussion (and I'm playing fpp games since quake 1).

    For me Vsync lag is much worse compared to MSAA lag. I will never play any game with vsync enabled :), screen tearing is bad, but mouse movements is much more important thing (at least for me)

    BTW, I have responsive gaming monitor, and corsair m65 gaming wired mouse, so hardware should not cause problems with mouse responsiveness in my case.
     
    Last edited: Aug 11, 2014
  14. fr33jack

    fr33jack Guest

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    true
     
  15. LuckyNumber8

    LuckyNumber8 Guest

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    In UT1 and ut 2003 even with MSAA I have INSANE frame rates, but it doesn't matter because I'm using framerate cap@60, and there's no fps fluctuations at all.

    I just shared my opinion on this topic, but I dont want to argue or force anyone to belive me :).
     
    Last edited: Aug 11, 2014

  16. dreamss

    dreamss Guest

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    higher gpu loads creates a non stable framerate

    non stable framerate+vsync = input lag
     
  17. Agent-A01

    Agent-A01 Ancient Guru

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    No... Just no.
     
  18. tsunami231

    tsunami231 Ancient Guru

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    right, If you are modify the original frame with any effect Be it AA or AO your adding to the time it need to render which in turn add to input lag.

    For the same reason Digital Noise reduction add to Input lag on HDTV or DNIe for that matter. and using PC mode reduces it cause all that extra stuff isnt added to the image. Same concept applies to AA/AO its just most time this effect is so little it cant be noticed.. Some will notice it others will not.

    But feel free to think adding effect to a original frame dont add latency in some way which will be compound if you cant keep stables fps

    Hell it happens in unreal engine game when AA is added even with good stable FPS.
     
    Last edited: Aug 14, 2014
  19. Agent-A01

    Agent-A01 Ancient Guru

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    Same FPS with AA = same frame time. Please quit talking out of your ass.
     
  20. octiceps

    octiceps Guest

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    Depends. Where in the render pipeline is that FPS/frame time number taken from? If taken from the beginning of the pipeline at close to game engine level like most software do (except FCAT which is a special hardware+software solution), it's not taking into account anything later in the pipeline which can add latency once it goes through the driver, OS, and display. V-Sync, triple buffering, poor frame metering, drivers, OS, laggy monitors etc. can all add lag despite no reported difference in FPS. So you never know, it is indeed possible that AA can cause additional lag on certain hardware, driver/OS, and game engine configurations. Unfortunately, the requisite test setup for determining this costs several times more than a souped-up gaming rig.

    I've never personally experienced driver-forced AA adding input lag, but I do distinctly remember forcing ambient occlusion in Nvidia Control Panel just after they added the feature and it adding an intolerable amount of input lag to Half-Life 2 even though the reported frame rate never dropped below 60. 100+ FPS felt worse than 30 FPS.
     

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