Strange activity trying to stop video playback screen tearing

[Petros_k]

Graphics Card: ATI Radeon HD 6450 (one HDMI and one DVI output)
latest Catalyst Control Center installed
dual monitors to duplicate (not extend) desktop
Windows 7 64-Bit


I noticed that my 26" TV monitor was suddenly getting screen tearing during video playback (not using my PC for gaming) after I troubleshooted my desktop and turned the Aero feature on in Windows 7, so I tried something. This is very odd to me because the desktop settings should be duplicated. In the Catalyst Control Center, go to Creating and Arranging Desktops, I noticed my other smaller monitor for the computer was set as the "preferred" monitor. If I right click on the TV monitor and select "Make preferred" the screen tearing goes away on the TV, but the problem then goes to the computer monitor. Switching this setting back and forth between monitors makes the screen tearing go from one monitor to the other.

Any clue why this would happen?

 

[LoveMachine]

I have a similar setup but with a 7750 and Onkyo AVR to Plasma 1080p TV with the same issue regardless of whether the HDMI cable runs to the AVR or TV. Might have something to do with different native refresh rates of each monitor. Perhaps the video card can only perfectly match one connection, and leaves the sloppier refresh to the secondary monitor. Various version of Catalyst have all had this.

 

[Petros_k]

I have a similar setup but with a 7750 and Onkyo AVR to Plasma 1080p TV with the same issue regardless of whether the HDMI cable runs to the AVR or TV. Might have something to do with different native refresh rates of each monitor. Perhaps the video card can only perfectly match one connection, and leaves the sloppier refresh to the secondary monitor. Various version of Catalyst have all had this.

That means every time I want to get the best picture on my larger monitor to view something like a Youtube 720p video I have to keep switching it to be the preferred monitor? This is hopeless unless the monitors are exactly the same resolution, refresh rate, etc?

 

[KingFatty]

As a test, can you run a 3D game/program in a window (on either screen) and try to duplicate the tearing - does the 3D game prevent tearing on either display?

 

[Petros_k]

Sorry, I have no games. I only playback HD video.

 

[LoveMachine]

That means every time I want to get the best picture on my larger monitor to view something like a Youtube 720p video I have to keep switching it to be the preferred monitor? This is hopeless unless the monitors are exactly the same resolution, refresh rate, etc?

AFAIK, yes. I also ran the iGPU in my 3570K with the same problem, so this isn't isolated to AMD. Perhaps others can chime in if they have better luck using Nvidia.

I don't think the monitors have to be exactly the same, but a computer monitor and a screen designed for TV/Movies are the same fundamental technology, but they are implemented differently when manufactured. For example, the EDID info for a plasma/LCD TV will register with another HDMI connected deviced as 59.9whatever Hz as it's native resolution, vs. a computer monitor that will register as a true 60Hz. The video card treats both as either 60 or 59.9whatever, with the secondary getting shafted by 0.012Hz. That small difference causes the tearing.

 

[Petros_k]

At least I figured out how to fix it for whatever monitor I'm viewing. I saw all kinds of suggestions that made no difference, including vsync settings (setting "verticle refresh on" in the AMD Catalyst Control Center 3D settings).

 

[KingFatty]

Does your motherboard have integrated graphics - a separate video "card" with its own ports on the motherboard?

If so, you could try connecting one display to the discrete graphics card, and the other display to the integrated graphics/motherboard.

But I still think you should at least try forcing the video card to use its faster video memory speed while running dual displays, to see if that fixes the issue. Typically video cards will use a slower memory speed that is "power saving" most of the time, and then switch speeds if you use video or 3D gaming. Three different memory speed profiles (2D/idle, video playback, and 3D, with increasing memory speed for each step). But the problem is when you use dual or triple screen, the chosen memory speeds may be just a bit too low and result in weird effects. So, as a work around, you can just ask the video card to use the faster memory speed all the time (with a very tiny cost of slightly increased power usage, very tiny). The easiest way is to just run anything that is 3D, it doesn't have to be a game, even the video card control panel will work if it displays anything in 3D (like a spinning cube to illustrate the various anti-ailiasing settings etc.).

If you can use that trick to verify the problem is fixed, then you can go ahead and take the next step of telling the video card to always use the faster memory speed by customizing the driver or video card BIOS settings.

 

[Petros_k]

...you should at least try forcing the video card to use its faster video memory speed while running dual displays, to see if that fixes the issue. Typically video cards will use a slower memory speed that is "power saving" most of the time, and then switch speeds if you use video or 3D gaming. Three different memory speed profiles (2D/idle, video playback, and 3D, with increasing memory speed for each step). But the problem is when you use dual or triple screen, the chosen memory speeds may be just a bit too low and result in weird effects. So, as a work around, you can just ask the video card to use the faster memory speed all the time (with a very tiny cost of slightly increased power usage, very tiny). The easiest way is to just run anything that is 3D, it doesn't have to be a game, even the video card control panel will work if it displays anything in 3D (like a spinning cube to illustrate the various anti-ailiasing settings etc.).

If you can use that trick to verify the problem is fixed, then you can go ahead and take the next step of telling the video card to always use the faster memory speed by customizing the driver or video card BIOS settings.

The above suggestion sounds very promising. I don't have Direct-X installed on my system, but doesn't that have a test for a 3D object? Is that what you're talking about? Should I just install Direct-X?




Regarding power, I was wondering if Windows is doing something without making it known (as usual). My current power option setting In Windows 7: Power Options > Advanced settings > "PCI Express > Link State Power Management" > Setting: Moderate power savings

When I hover over the setting it says "Attempt to use the LOS state when link is idle"

Could it be that when my TV is off Windows detects there's only 1 monitor output that's active and it degrades the second output to the TV when it's off?