I cite the the user soundstar3 from the apple led thread here:
"Have you ever experienced the issue with your s3 where you see faint lines going across the screen? I have, and it's an issue that is well documented. I can tell you from experience, it's annoying. Many people have said turning off hw overlays in developer options solves the problem. The sad thing is, it only minimizes the issue and you have to select the option again whenever you reboot. Not only that, the gpu is stuck doing the work which adds lag to the the phone. Well guys, I've found a real solution. However, you have to be rooted. There's an app called pimp my rom, it's very useful. If you open it and go to tweaks, enable and disable features, you should see a surface dithering option. Check it and reboot. Bam! No more problems with screen flickering. I have been able to confirm this on a few s3 devices that this does indeed solve the issue. If you have ever experienced this problem, please try my solution. I hope this helps!"
So i'm not sure if its the dithering or the screen flicker, that i was able to deactivate this way.
I hope that it's the flicker because it seems to be way easier to buy a flicker free screen/laptop than to find a solution for dithering on macbooks or windows laptops.