Help! LG 19" Flatron and DVI input lag and stuttering in OSX (any version, any ATI board)

[Toadman]

Hello. Didn´t know quite where to put this, so please move topic if necessary.

 

I have posted this problem previously on this topic:

 

http://www.insanelymac.com/forum/index.php...p;#entry1427730

 

I Have the following two rigs:

 

Core 2 Duo E6300

5GB OCZ DDR2 800

P5B Deluxe Wifi

Powercolor HD4870 512mb DDR5

Seagate 1TB HD

AOC 22" 16:10 monitor

Vanilla EFI boot 10.6.2, Cham RC4, Graphicsenabler=yes

 

and

 

Core Quad i5

4GB Generic DDR3 1333

GA-P55M-UD2

Saphire HD4670 1GB DDR3

Seagate 1TB HD

LG 19" 5:4 Monitor L1952H

Vanilla EFI boot 10.6.2, Cham pre-RC5 compiled from source (modded ati.c file to Motmot for VGA, other framebuffer mods discussed in posted topic), Graphicsenabler=yes

 

I get weird input lag and video stuterring with the LG 19" Flatron display (L1952H) that I don´t get with my other AOC monitor and with my 1080p LED LG TV. It is present in any OSX computer with any ATI board.

 

It also persists in dual monitor and affects the other monitor as well, even if it actually functioned fine alone.

 

I´ve noticed that the video stutering is ciclical and regular (once every 5,4 seconds), affects all resolutions and screen frequencies, in programs, games, 2d or 3d, even in calculous programs, not graphics card dependent, limited to this display only.

 

It has no such problems with D-sub (VGA/RGB...), problem does not exist in Windows or Linux/BSD.

 

I´m thinking this has something to do with Framebuffer or OSX ATI drivers and refresh rate/frequency post errors/incompatibility, but I can´t be sure. It might explain the discrepancies i noticed in my previous post in the cited topic. Appears to be present in every ATI framebuffer, I don´t have any NVIDIA for tests.

 

I have no idea of how to fix this, I´ve found a nice article here, though, that might explain the issue, but, then again, might not.

http://www.behardware.com/articles/632-1/l...o-crts-yes.html

 

If anyone has ever had this problem and have fixed it or not, please post. I have no intention on buying another LCD display just to adress this issue.

 

Untill this is resolved, I am using it with D-sub (VGA/RGB...)

Thanks in advance, if I find a solution first, I will post.

 

Toadman

[bbeepp]

It's a common problem with ATI on certain LCD dislplays :/ Even Mac Pro users have same issue with 4870 gfx board. It's known to Apple but they seem not to care and suggest buying a compatibile display :/

 

 

More on apple forums...

[Toadman]

Thanks for the post.

Now I know I can give up and wait for better drivers (Although it seems to be an issue with no solution for quite a while, I don´t think it wil ever be fixed...).

 

Thanks

Toadman