How do I get rid of 'horizontal shearing'?

chocky909 · 29 Jul 2011 at 02:22

I recently got myself a new gaming PC with an Intel Core i5 2500K overclocked to 4.2GHz with 8gb RAM and a GeForce GTX 570 3D card. I'm getting good frame rates on demanding games like Crysis and Metro 2033 at ultra settings but I'm getting some weird artifacts. It's like a horizontal shearing or bands of flashing and it's there even on the low res FMV and during the opening credits so I dont think it's due to the strain on the processor. Also it makes no difference whether I run in low or high settings and I've played with all the anti aliasing settings I think too. Only some games have this problem and I have no problems with video or any other aspects. I'd google the phenomenon but I have no idea what it is. I'm quite new to PC gaming as I've always had cheaper PCs but I'm keen to make these games look their best so if anyone has any ideas about what causes this effect and how to get rid of it I'd be immensely happy.

EDIT: I just realised this might have been better posted in the Games forum, sorry if so.

kiel367 · 29 Jul 2011 at 02:43

this is called screen tearing, try turning on v-sync

chocky909 · 29 Jul 2011 at 04:08

In 9 words you have solved my problem that has been nagging me since I bought this PC a month ago. Thanks a lot. Crysis looks about 500% nicer now!

BTW, I went to the Nvidia Control Panel>Manage 3D Settings>Global Settings>Vertical Sync>select "Force On".

Would it be better to change this setting only for the affected games or is it generally fine to set this for all programs?

Final8y · 29 Jul 2011 at 05:26

chocky909 said:
In 9 words you have solved my problem that has been nagging me since I bought this PC a month ago. Thanks a lot. Crysis looks about 500% nicer now!

BTW, I went to the Nvidia Control Panel>Manage 3D Settings>Global Settings>Vertical Sync>select "Force On".

Would it be better to change this setting only for the affected games or is it generally fine to set this for all programs?

If the Games have the V-Sync option built in then use it from within the game & use the Nvidia Control Panel Vertical Sync>select "Force On" when a particular game does not.

Dutch Guy · 29 Jul 2011 at 14:34

Final8y said:
If the Games have the V-Sync option built in then use it from within the game & use the Nvidia Control Panel Vertical Sync>select "Force On" when a particular game does not.

This is what I do as well.

I setup each new game in the separate 3D settings of the game in the drivers.

chocky909 · 29 Jul 2011 at 14:59

Cheers. Annoyingly though Nvidia Control Panel only recognises the Steam client and not the individual games.

Dutch Guy · 29 Jul 2011 at 15:05

chocky909 said:
Cheers. Annoyingly though Nvidia Control Panel only recognises the Steam client and not the individual games.

Add them manually by mentioning the exe file.

Duff-Man · 29 Jul 2011 at 18:06

Since you're new to vsync, be aware that there are two different modes of vsync.

"double buffer" vsync (the most common mode) stores an extra frame in the framebuffer, and waits until the screen refreshes before outputting it, to avoid tearing. "Triple buffer" vsync is similar, but stores two extra frames in the buffer.

Double buffer vsync will only allow your framerate to be an integer division of your monitors refresh rate: That is, you will only be able to get 60fps, 30fps, 20fps, 15fps, 12fps, 10fps (etc). If your GPU is not capable of rendering 60fps, your framerate will drop to 30, and so on. These sudden changes in framerate can be a little annoying. Triple buffer vsync on the other hand allows you to output frames at any framerate.

The downside to enabling vsync is a lag between giving a command and seeing it on the screen (due to the frames being stored in the buffer for a time). This can make a game feel sluggish and "muddy". Triple buffer will have a higher lag than double buffer, and a 120Hz monitor will have a much lower lag than a 60Hz screen. The exact amount of lag depends on where the screen is in its refresh cycle when the frame is completed, but the range of lag values is as follows:

* 60Hz double buffer ('regular') vsync: 16.7 to 33.3ms lag
* 60Hz triple buffer vysnc: 33.3 to 50ms lag

* 120Hz double buffer vsync: 8.3 to 16.7ms lag
* 120Hz triple buffer vsync: 16.7 to 25ms lag

For this reason a lot of people consider a 120Hz screen to be great for gaming, even if they aren't using it for 3D. It allows vsync to be enabled with very little extra lag. Also you get more "divisions" in double buffer vsync [120, 60, 40, 30 etc]. Dropping from 60fps to 40fps is not nearly as annoying as dropping from 60fps to 30fps.

-Aura- · 29 Jul 2011 at 22:42

Duff-Man said:
Since you're new to vsync, be aware that there are two different modes of vsync.

"double buffer" vsync (the most common mode) stores an extra frame in the framebuffer, and waits until the screen refreshes before outputting it, to avoid tearing. "Triple buffer" vsync is similar, but stores two extra frames in the buffer.

Double buffer vsync will only allow your framerate to be an integer division of your monitors refresh rate: That is, you will only be able to get 60fps, 30fps, 20fps, 15fps, 12fps, 10fps (etc). If your GPU is not capable of rendering 60fps, your framerate will drop to 30, and so on. These sudden changes in framerate can be a little annoying. Triple buffer vsync on the other hand allows you to output frames at any framerate.

The downside to enabling vsync is a lag between giving a command and seeing it on the screen (due to the frames being stored in the buffer for a time). This can make a game feel sluggish and "muddy". Triple buffer will have a higher lag than double buffer, and a 120Hz monitor will have a much lower lag than a 60Hz screen. The exact amount of lag depends on where the screen is in its refresh cycle when the frame is completed, but the range of lag values is as follows:

* 60Hz double buffer ('regular') vsync: 16.7 to 33.3ms lag
* 60Hz triple buffer vysnc: 33.3 to 50ms lag

* 120Hz double buffer vsync: 8.3 to 16.7ms lag
* 120Hz triple buffer vsync: 16.7 to 25ms lag

For this reason a lot of people consider a 120Hz screen to be great for gaming, even if they aren't using it for 3D. It allows vsync to be enabled with very little extra lag. Also you get more "divisions" in double buffer vsync [120, 60, 40, 30 etc]. Dropping from 60fps to 40fps is not nearly as annoying as dropping from 60fps to 30fps.

What an excellent well put-together post.

Duff-Man · 29 Jul 2011 at 23:26

-Aura- said:
What an excellent well put-together post.

Why thank you kind sir

rounddodger · 30 Jul 2011 at 00:46

+1 interesting explanation!

Ste · 30 Jul 2011 at 13:02

Great post - could I ask, does the extra buffering etc. have any effect on VRAM requirements?

Duff-Man · 30 Jul 2011 at 13:15

Ste said:
Great post - could I ask, does the extra buffering etc. have any effect on VRAM requirements?

Very little, actually. You only need the space to store the extra one (or two) frames. So at 1920*1200 with 32bit colour that's around 8Mb extra VRAM for double-buffer, or around 16Mb for triple-buffer.

This used to be significant ten or twelve years ago when GPUs had ~32Mb, and is one of the main reasons why double- rather than triple-buffer vsync became standard. But in these days of Gb+ cards it's really not an issue.

Overslop · 30 Jul 2011 at 13:28

-Aura- said:
What an excellent well put-together post.

Agreed, should be made into a sticky along with other useful explanations of common graphics card-related features.

Fancy producing an entire topic Duff-Man?

phil-k · 30 Jul 2011 at 13:39

I dont get tearing in games but do in cut scenes introductions etc

Duff-Man · 30 Jul 2011 at 13:39

Overslop said:
Fancy producing an entire topic Duff-Man?

Heh

I could do, I suppose...

If I did, what else would you guys want to see in there? Other than vsync I guess there's:

- memory useage / paging
- CPU limitation
- microstutter and other multi-GPU issues
- AA and AF etc
- Power draw and cooling

Anything else I've missed?

arc@css · 30 Jul 2011 at 14:26

Looks like a great, worthwhile list of topics (CPU limitation would be especially useful).

Ste · 30 Jul 2011 at 15:25

Ah thanks, looks like it's time to try and force triple buffering...

Getting the most out of crossfire took me a bit of research, anything on that would be great. I wonder if we could keep a list of known multi GPU issues in there too that are not published in release notes (eg crysis 2 dx11 MSAA breaking crossfire scaling)...

Thanks again

chocky909 · 30 Jul 2011 at 20:14

Hey guys. This is all very interesting but unfortunately I've encountered a problem. I've had my PC connected to both my 24" Dell monitor and my 50" Pioneer plasma to watch video on. Now since I got the PC, video has been perfect but since I started messing with vertical sync I'm getting awful screen tear on most video and games but only on the plasma. This isn't good because I use the PC more for video than gaming. I've also noticed the plasma behaving oddly like when I make the Winamp Milkdrop visualiser fullscreen the sound cuts out and the screen goes blank for a few seconds which it never did before.

I've played with the 3D settings and also experimented with the multiple display settings but I'm not having much joy. Any ideas?

Tute · 30 Jul 2011 at 20:25

Nice one Duff-Man, always wondered what Triple and Double Buffered VSync entailed.