Acer XB280HK Gsync Causing Fps Drops?

admaster99

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Jan 27, 2014
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So I bought an Acer XB280HK display about 6 months ago thinking it would solve all my fps stuttering problems and it seems to have made them worse. I've noticed on most games at random times the fps will drop slightly like 4-5 fps and the higher the graphic settings are the worse it gets. Like in black ops 3 and witcher 3 it will drop below 40 fps at times for no apparent reason. I can understand that when you push your computer to hard the fps is going to decrease but these are random fps drops.

So I guess I'm wondering if this is normal? Or if maybe my monitor is faulty? I did a quick video and posted it on youtube as an example, its a little long but it demonstrates whats happening. To be honest games feel smoother with gsync disabled.

https://www.youtube.com/watch?v=tDol94a3n-4

My Specs:

ASUS Z170-A ATX DDR4 Motherboards
i5 6600k
G.SKILL Ripjaws V Series 16GB (2 x 8GB) 288-Pin DDR4 SDRAM DDR4 3000
Asus Strix GTX 980
Cooler Master 750 Watt PSU
 
Solution
Update!

Just updating this post in hopes of helping anybody in the future who experiences this issue or something similar.

I believe I have figured out the root of the problem. I'm not sure exactly if its driver specific or monitor specific but apparently with gsync if you go out of the supported range which I believe is 30-60 fps on the particular monitor I have, gsync will stop working. Resulting in mostly screen tearing. But for whatever reason the monitor I currently have in my possession, gsync only works between 30-57 fps. If I play the nvidia pendulum demo and set the settings to gsync at 60 fps it tears like crazy.
If I cap the fps at 57 fps the screen tearing completely disappears. So I tried this same...
How are you locked to 60FPS if you are using GSYNC?

With GSYNC the GPU simply creates a new frame, then the monitor gets it a very short time later and draws it. I suppose if using an FPS CAP method it might cause some issues with frame drops, but it's not clear what you're doing.

Anyway, it may be an issue specific to this game since GSYNC works quite well for everybody I've talked to.
 
From what I read Nvidia updated gsync a while ago where now you have to have vsync on in order for gsync to work. So thats whats capping the fps at 60 because vsync caps the fps at the refresh rate of the monitor. I have no fps limiters on.

I just want to make sure there is no settings or software problems I'm missing that is causing this. I also want to make sure the monitor is not faulty because I am thinking about selling it and I don't want to sell a faulty monitor.
 
I also just played another round of Black ops 3 and it dropped into the 40 fps range many times which causes very noticeable stuttering.

Yea I watched that video posted and his fps drops really low also maybe I'm just being to picky, I just don't understand why it only does it while gsync is enabled.
 
1) GSYNC and VSYNC can not run at the same time.

a) GSYNC-> GPU creates frame, sends to monitor and it's drawn almost immediately
b) VSYNC-> GPU creates frame, which is then held in a BUFFER so the monitor can update on the next draw cycle (to avoid screen tear, but it adds some lag)

If you have both enabled, then VSYNC is just acting as the default option for 60FPS and above output from the GPU. I thought VSYNC OFF was another option for 60FPS+.

2) a big PROBLEM with having a 60Hz, GSYNC monitor is that it's difficult to stay in the asynchronous range (below 60FPS). You have to be both:
a) in GSYNC mode, and
b) have CAPPED the FPS somehow (to below 60FPS, I remember for 144Hz monitors 135FPS was chosen by some though I don't know the specifics. Perhaps try 50FPS first if possible. I don't know how to force a cap though AMD added it as a global option.)

I don't have GSYNC so I can't walk you through that, but those are the facts.

UPDATE:
My best guess for your problem is that you are running VSYNC ON when it shows 60FPS, and when you see the dips you're running in GSYNC mode, though not sure why that causes stuttering.
 
Yea I see what your saying and I really appreciate your responses. But if I turn vsync off with gsync enable I get screen tearing and it also continues to stutter. I have tried every possible option and it seems like it's just not running as intended. And it's frustrating because I can't just return the monitor because its refurbished so it came as is. Maybe I should do a fresh install of windows and see if that makes a difference. I just hate to do all that work for nothing.
 
If you are getting tearing with gsync on there is something wrong. Gsync cause no tearing whatsoever, that is the main selling point of gsync/freesync. You need to have vsync ingame disabled as well.

Have you tried doing a clean install of the driver with DDU?

But yea it will cap the fps at your monitors refresh rate, that is normal. It acts like vsync but without the side effects vsync can cause (like increased input lag). Also it won't drop your FPS to stay in sync like vsync does. With vsync on if your FPS drops below 60, it will lock in at 45 FPS. Lower than 45 and it locks at 30 then 15 etc. Gsync/Freesync avoids this issue entirely.
 
Thanks for the response "SinxarKnights" but I have seen from multiple sources that vsync must be enabled for gsync to work. If I disable vsync I get terrible screen tearing with gsync enabled. But if I enable gsync + vsync at the same time games seem to play like they would with just vsync on. I'm starting to believe gsync is a huge waste of time and money not impressed.

Source:
https://www.reddit.com/r/nvidia/comments/3ne6lg/gsync_tearing_with_vsync_off/ "I've confirmed with ManualG and My friends at EVGA that as of right now in order for Gsync to work Vsync must be enabled. Turning off Vsync with disable Gsync."
 


I don't have GSYNC, but if you actually DO have to have VSYNC ON for GSync to work, they would not be on at the same time.

*It's 100% true that VSYNC and GSYNC can not function at the same time. No if, ands or buts.

VSYNC would kick in any time you output more than a specific FPS (whatever your max is). GSYNC would work any time below that.

So...
1) I'm sorry that GSYNC doesn't appear to be working, though I'm not sure how to help at this point.

2) Note that it's a 4K monitor thus limited to 60Hz. GSYNC range is below 60FPS. Any time you output 60FPS or higher you default to VSYNC ON. I may have said that already.

As per the video, there really should be no reason for GSYNC to perform worse than VSYNC ON so I'm confused on that:
a) if outputting at least 60FPS both scenarios should be the same (VSYNC ON)
b) if dropping below 60FPS with GSYNC OFF, but VSYNC ON you should get judder (quick stutter)
c) if dropping below 60FPS with GSYNC OFF, and VSYNC OFF you should get screen tearing
d) if dropping below 60FPS with GSYNC ON, game play should remain fairly smooth with no screen tearing. You could s till get stuttering as GSYNC if the FPS is really low, but it shouldn't be low if it's normally fine with VSYNC ON (GSYNC OFF).

3) DDU is worth trying as suggested. I doubt reinstalling Windows will help.

4) The ONLY thing I can think of is that the monitor's GSYNC module is somehow defective.

5) Any way to test with another compatible PC?

*How GSYNC works:
Normal monitors refresh the screen at a set interval. For 60Hz monitors that's every 1/60th of a second. This is problematic if the GPU is a bit late updating the FRAMEBUFFER. If VSYNC is OFF you end up with screen tearing because part of the image gets updated and part does not.

With VSYNC ON you force the monitor to grab the new frame only during a very short time within that 1/60th of a second. It then draws the new frame. The main drawback is it makes things a bit more sluggish because the frame has to be buffered and sit there until the monitor can grab it and draw it.

Another issue with VSYNC ON is that if you can't output at least 60FPS (for 60Hz monitor) from the GPU then you miss the next refresh cycle. Over the period of a second you'll get a mixture of 1/60th, 2/60th, and possibly higher times for each frame. This causes a JUDDER (quick stutter) effect.

Thus, GSYNC->
The GPU outputs its frame as soon as it can be processed then a very short time later the GSYNC module gets it and the monitor draws it. The GPU can take slightly longer to process the next frame, but when done it still takes the same amount of time to draw it. So it's like drawing a picture and handing it to your friend to look at. You may vary how long it takes to draw your pictures but your friend grabs it and looks at it in the same amount of time.

If you haven't forced a CAP (which is possible) the FRAME TIME will be different every single time but the experience is quite smooth.

Why can't VSYNC be ON at the same time as GSYNC?
As I said, VSYNC is for when the monitor is updating at a preset interval. We call this SYNCHRONOUS. Again, the GPU creates a frame, this sits in a buffer, then the monitor grabs it during a very short window.

GSYNC again is when the GPU creates a frame and the monitor draws it a very short time later. The time between frames is different every time. This is called ASYNCHRONOUS. Not synchronized.

 
Update:

1) I did some Googling and it appears some people have FPS drops due to the NVidia drivers. Some versions seem to work better than others. I don't know why.

2) As I read again, I see you started with the fact that you have had stuttering problems before and got this to help fix that. This makes me think your PC is the main problem, and that the GSYNC monitor may be working fine.

So in that case, maybe reinstalling Windows will help.

3) other than some of the NVidia drivers apparently causing issues, I can't find anybody saying GSYNC is physically broken on the monitor
 


Suit yourself!
 
Thank you all for your time and responses especially "photonboy" I really do appreciate it. I'm not trying to contradict anything anybody has stated. I was just stating what I have read, I completely agree 100% that vsync should not have to be on in order for gsync to work. And was completely surprised when I first bought the monitor and enable gsync and was still getting screen tearing.

I do not have a readily accessible 2nd computer but I do have a second harddrive around so I think this weekend if I get time I will do a fresh install of windows and see if that makes a difference.

Also another thing to point out is I download the nvidia g-sync pendulum demo and it seems to work fine. Is it possible that is just the 2 games that have problems? Which are COD Blops 3 and The witcher 3 those are the ones that always seem to have the stuttering problems, though the screen tearing with just gsync enabled still happens on all games.
 
Update!

Just updating this post in hopes of helping anybody in the future who experiences this issue or something similar.

I believe I have figured out the root of the problem. I'm not sure exactly if its driver specific or monitor specific but apparently with gsync if you go out of the supported range which I believe is 30-60 fps on the particular monitor I have, gsync will stop working. Resulting in mostly screen tearing. But for whatever reason the monitor I currently have in my possession, gsync only works between 30-57 fps. If I play the nvidia pendulum demo and set the settings to gsync at 60 fps it tears like crazy.
If I cap the fps at 57 fps the screen tearing completely disappears. So I tried this same concept on all the games I was having problems with and it worked, I get no screen tearing or stuttering only the occasional fps drop from intense scenes or the game loading. So to reiterate I can only get gsync to work properly on my monitor if I cap the fps at 57 and this is also with no vsync enabled.
 
Solution