Dell 2412M Ultrasharp Issues

[deshstar]

Hi,

So I have a Dell 2412M Ultrasharp monitor, currently it is connected via mini display port adaptor to DVI cable to my 2010 MBP (2.66 i7, 8GB, 256 SSD, NVIDIA GT 330 512GB, Hi Res Anti Glare) running Mountain lion.

I am experiencing a couple of display issues.

1.) Very fine vertical banding. This is only really apparent when darker colours are displayed on screen. Best example would be the general CS6 interface.

2.) Flickering when displaying expanses of white. Best example, this website.

I also have a 2008 Mac Pro (2.8 Xeon Octo, 10GB, 128SSD, 2x 1TB, 1x500Gb, FLASHED HD 4870 1GB, 2600XT 256GB, ML). When connected to this setup I get the exact same thing, using either video card. But here's the thing; when I launch bootcamp / Windows 7 I don't have the same problem, I've tested using
a range of different solid coloured wallpapers and they all display correctly.

I have the app Switchresx on both machines and have tried tweaking a couple of settings like the refresh rate etc but I will hold my hands up and say that I don't know what I am really doing here i just wanted to see if I could make a difference.

It's worth mentioning that I have also tried a couple of different monitors that I have knocking about and they also display fine, so it must be something between the Mac / Mountain Lion / 2412M Monitor.

Can anyone offer any ideas to fix this? I'm a graphic designer by trade so it's quite critical that solve the problem.

Thanks in advance,

Ben

 

[3rd Rock]

Same monitor OP, but I have a Mac Mini 2011 hooked up with a Mini Display Port/HDMI cable, not DVI as you have it. Might this help if you have a HDMI input on the MBP ?

 

[deshstar]

Curious how you are connecting it like that as the monitor doesn't have a HDMI input?

 

[zepman]

I also use the U2412M but with a 2009 MBP. I had the same problem. It turned out that it's a problem with the Nvidia graphic driver on the Mac. U2412M is a 6-bit monitor and it's dithering to be able to show all desired colors. The Mac graphic driver also tires to dither for the same reason. This results in a conflict as they both use dithering. This generates the problems OP describes.

The solution is to turn of graphic driver dithering for external monitors. This is done by a hack that can be found in this thread.

Here's a direct link to the post containing the latest version of the hack.

A simple way to install the kext is to use the application Kext Drop.

 

[deshstar]

WOW

Unbelievable. Fixed!

It's like looking at a new display, thank you SO much!

 

[3rd Rock]

Curious how you are connecting it like that as the monitor doesn't have a HDMI input?

Sorry, but glad you got it to work....HDMI on my MacMini not monitor. Guess you don't have one on your notebook ?

 

[zepman]

Sorry, but glad you got it to work....HDMI on my MacMini not monitor. Guess you don't have one on your notebook ?

I don't think it matters if you use DVI or HDMI. In your case it works because the HD3000 in your Mac Mini does not have the bug.

 

[deshstar]

Just curious, why is it that i was experiencing the same issues on the Mac Pro with both it's ATI cards?

 

[3rd Rock]

I don't think it matters if you use DVI or HDMI. In your case it works because the HD3000 in your Mac Mini does not have the bug.

Good enough. Thanks for the update

 

[zepman]

Just curious, why is it that i was experiencing the same issues on the Mac Pro with both it's ATI cards?

It was reported in the thread I linked to that drivers for some older ATI-cards also was affected by the bug. Sadly there's no solution for the ATI-cards as the hack only works for Nvidia.