Vertical Sync on large LCDs

Toggle sidebar Toggle sidebar
D

dphilips

Distinguished
Oct 30, 2008
4
0
18,510
We are running various digital signage software on large format LCDs (Samsung and LG TFT/LCD displays 37" and larger). We are seeing issues with scrolling text within the the player software "stuttering" on the large LCD displays. This issue seems to be pronounced when using ATI cards or mid to low-end NVidia cards. We think we have narrowed the problem down to the Vertical Sync between the graphics card and the LCD, but we cannot fix the problem consistently using this approach. Forcing V-Sync on in the NVidia Control Panel sometimes helps, but we cannot find a similar setting in the ATI Catalyst control panel.

Has anyone experienced similiar issues with scrolling text on large LCD screens?
 
D

dagger

Splendid
Mar 23, 2008
5,624
0
25,780
What are the cards in question? And at what resolution? If it's very low end cards or onboard, working at typical resolutions of such a huge display, the screen-tearing is normal. The gpu can't handle even in 2d mode given the resolutions. You can often see the tearing on old budget PCs on normal monitors while surfing.

Lower the resolution and see if the problem disappears at some point. It's no resolution, but may identify the problem.
 
D

dphilips

Distinguished
Oct 30, 2008
4
0
18,510
Cards we have tested (that I can remember):

ATI 2400 HD Pro (much text stutter)
ATI 2600 HD Pro (much text stutter)
NVidia 8600 (some text stutter)
NVidia 8800 (inconsistent results; less stuttering)
ATI 2900 XT (inconistent results; less stuttering)

We have found GENERALLY that it the text scroll stutters less in lower resolutions (1280 x 768 and lower), but sometimes, with some cards, it will stutter on ALL resolutions. These screens are all 1920 x 1080 maximum resolution, and ideal we'd like to figure out if there is optimum hardware (or software/driver/configuration settings) to eliminate scrolling at any resolution.

Like I mentioned, we know where the VSync setting is in the NVidia control panel, but haven't found a similar setting in ATI's Catalyst.

I am aware of the tearing issue, and we've experienced that also in some instances, but I believe the stuttering text scroll is actually separate from the tearing. I've seen screens exhibit both issues, one issue or the other, and neither issue.
 
murdoc

murdoc

Distinguished
Aug 5, 2008
356
0
18,780
I seem to get stuttering as described too in bully and in TF2 (under certain servers). I'm not sure why either. The weird thing is I'm using ATI 4870 1GB too... which doesn't make any sense. My monitor is a 22" Samsung T220 and I've set the mode to gaming for RTA =/

I have the latest drivers (Catalyst 8.10 FC2 patch edition). Anyone can shed some light into this?
 
D

dphilips

Distinguished
Oct 30, 2008
4
0
18,510
Upon further testing, we have our suspicions that's it's a DirectX issue with LCD screens, but we can't determine that exactly, and as hardware folks, we are not quite sure what we can do about it if it is.

Anyone else experience these issue?

We've also just tested with similar results on a NVida 9800 on a 19" LCD and a 46"LCD. Text stutters (ever so subltly) when scrolling across the screen. FPS for the software hovers between 59.5 and 60.5 while the txt scrolls. Can't determine for sure if a certain FPS triggers the stutter or not.
 
murdoc

murdoc

Distinguished
Aug 5, 2008
356
0
18,780
Well generally any FPS over 30 is sufficent. Your eyes can't take more than 30 so you really won't see a difference. So stuttering shouldn't be an issue even if you cap it at 60 fps. It helps a little if your monitor can set to a fast response mode (like my Samsung T220) which gives me the option to set the RTA between off, 2ms, 5ms.
 
D

dphilips

Distinguished
Oct 30, 2008
4
0
18,510
The FPS reading is a feature of the CG Software that renders text and graphics for the digital signage application. It takes a reading about every second for the amount of FPS the CG app is generating. The actual number moves above and below 60FPS consistenly (ie. 60.13, 60.00, 59.65, etc). We have suspicions that when the FPS is a fraction above and below the refresh rate (which is 60Hz for all LCDs), that since it isn't divisible equally by 60, this is causing display issues. Are we correct to assume that this woudl be the case?
 
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom