Hi everybody,
Yesterday I got myself a new laptop with Core i7 / nVidia GT630M combo. Before this I had Core i5 / ATi 5850HD combo. First thing I noticed were the almost transparent vertical lines on the screen - I've seen them before on my old laptop when Intel iGPU was selected in Hybrid graphics settings. Selecting ATi card resulted in perfectly normal output picture. So I tried to force nVidia GPU and apparently you cannot do that with nVidia since even when the proper GPU kicks in the image is fed to the display by iGPU.
So I went on Google and after a few hours found the exact description of the problem: dithering issue with Intel's iGPUs: http://forums.macrumors.com/showthread.php?t=905151&page=3
It has been there since first iGPUs and Intel never seemed to care. But now that I cannot force a proper GPU in the settings I would like Intel to notice this really annoying issue and release a solution.
The page to test the picture: Black level - Lagom LCD test
It looks a lot like static dithering example from that page except for it is vertical and shows up every 5 pixels or so. I used to think it was a display issue or something wrong with my particular iGPU on the old laptop, but now I've got 2 laptops with iGPUs with release dates separated by 3 years and I'm pretty sure it's something with either Intel's drivers or the hardware design.
Connecting another external display to VGA slot does not result in any similar issues on it.
Tech details:
Old laptop with same issue: Acer Aspire 7745G, Core i5 450M + Radeon HD 5850, Win7 SP1 x64
New laptop same issue: Dell Inspiron 17R 5720, Core i7 3612QM + GeForce GT 630M, Win7 SP1 x64
Latest drivers in both cases, 8.15.10.2761 that is.
I will be happy to provide any further details and cooperation as long as this issue gets noticed by the devs.
Regards,
Georgi