I recently updated my GPU from dual HD6950s to a single GTX780 and I have been experiencing issues with the color output over HDMI. Prior to the upgrade, my display looked beautiful, but with the NVIDIA drivers (I have tried the three most recent versions) everything is washed out. Additionally, it appears impossible to achieve "true black" via HDMI. Now where this becomes bizarre is when you also consider that I have a monitor connected via DVI that displays color perfectly and has true black with no adjustments to the NVIDIA driver settings.
To be clear, nothing else changed besides the GPU. I am running the exact same setup, HDMI cable, DVI cable, and so on.
I've been digging around on the internet for about a week now trying to find a different solution, and I have been discussing this on another board, but their GPU section is rather inactive so I'm reaching out for help here as well.
At first I thought it was the dreaded EDID extension issue, but I am unable to confirm this. The tools used to extract and modify EDID info are not compatible with Windows 8, and my attempts to manually extract the EDID from the registry and modify nv_disp.inf to ignore the flags have been fruitless. I am not sure if this indicates this was not the issue, or if I was unable to resolve it properly. I don't think this is a worthy avenue of pursuit unless someone has intimate knowledge of the method used to store EDID data in the Windows 8 Registry, as well as the structure of the nv_disp.inf file since it has also changed dramatically from what is described on various forms where this was discussed previously. By the way, nv_disp.inf is almost 12,000 lines long ... so that makes trying to figure it out really not-fun, especially with "less than helpful" section names like "Section001" through "Section 181" with subsections that all have the same names.
A helpful commenter on another board suggested that this was a result of the NVIDIA driver defaulting to a limited dynamic range over HDMI. I believe this is the same issue that the EDID bug was supposed to fix, and now you can change it in the control panel. I adjusted the Dynamic Range on this output to "Full 0-255" from "Limited 16-235" but there was no impact on the images rendered. I suspect that this only applies when certain video content is displayed, but this issue is global (meaning that it even effects the desktop).
I have uninstalled the drivers countless times, rebooted, performed clean installs, used driver cleaners, reset my monitor to factory defaults and tinkered to no end, but I am unable to make the HDMI output render correctly. Unfortunately, all this monitor has is HDMI and VGA, so I'm more-or-less stuck with HDMI.
Here are a few other relevant pieces of information:
*The monitor is connected directly to the GPU, no receiver or other equipment is in-line
*My OS is Windows 8.1 X64
*The monitor is an Acer S273HL
*The NVIDIA CP shows the monitor connected as "HDMI - HDTV"
*There are no Windows 8 drivers available for this monitor, but I was able to install the Windows 7 drivers if I disabled Signed Driver Verification - this had no impact in the issue
Here are some images to help illustrate the issue. You can see on the SMPTE test pattern that the blacks are completely washed out and display as gray. This is consistent regardless of the content displayed. Also included are screenshots of my NVIDIA Control Panel settings.
http://imgur.com/a/Py9Dz