Hello I am wondering if there's a way to safely force 6bit color WITHOUT the frc? With windows 7 of course since anything newer can't do 6bit I guess. I would never consider 6+2 but I already have a sun vision rlcd monitor in my possession for awhile now, thinking of at least retrying it before listing it on eBay(unless anyone here is interested in it) if it's possible to safely run 6bit only without +2frc with win7.
Have we established whether this is possible via EDID override in Windows?
There are a few HP zbook laptops at work with apparently native 6-bit screens, which appear very stable and calm to me. Windows 10 display settings reports 6-bit color, and I can see extra pixelation in the standard Windows 10 wallpaper, suggesting true 6-bit color.
I don’t know whether this is possible on an external display via EDID override. When I get a chance, maybe I’ll test that with my Epiphan capture card with a tweaked EDID.
macsforme I'm not exactly sure. I will say that I know Nvidia quadro gpus with their quadro driver actually allows you to import a edid that instructs the driver but unsure if a modified edid imported would actually turn off the frc. If you can test on the card that would be awesome! Multiple people have said that 6bit only is no longer possible on modern windows so thought all win10 isn't capable unless it that's for versions after 1809
jordan Multiple people have said that 6bit only is no longer possible on modern windows so thought all win10 isn't capable unless it that's for versions after 1809
Quite possibly Windows 10 does not allow you to set 6-bit color electively, but as I mentioned above, several laptops at my work do indicate 6-bit color in Windows 10, and there is pixellation on the desktop to match.
Unfortunately, my initial experiments with uploading a modified EDID with 6-bpc color to my Epiphan card did not cause Windows to report 6-bit color in the display settings. I tried every output port from my GTX 1080, with various combinations of rebooting (or not) in between connections, and it always showed 8-bit color on the external monitor (capture card). I also booted into an Ubuntu live USB installer (with the 6-bpc color EDID in effect), and Ubuntu also reported 24-bit color. I ordered an EDID spoofing device to try as well, but my initial impressions of this method are not positive. I wonder how the above-mentioned laptop displays are different; possibly something in the BIOS? I may try to dump EDIDs and/or try to determine their display models to investigate further.
macsforme I investigated a bit further into 6-bit color on Windows 10. I considered three possible triggers for this, based on my own observations plus insights from others here:
One of the specific machines I observed this on (an HP Zbook 15u G4) has an Intel i7-7600U CPU with an Intel HD Graphics 620 integrated GPU. There actually seem to be a fair number of reports from people experiencing 6-bit color reported by Windows 10, primarily bug reports where the behavior was undesirable (but may be helpful for us). Most of the reports also seemed to be for laptop screens. There were reports that the issue manifested on certain Intel driver versions, and that certain older versions of the Intel graphics control app allowed you to elect 6-bit or 8-bit color. I will post links to a few of the topics I found for further discussion: 1, 2, 3
Again, most of the reports were for laptop screens, although there was at least one report regarding an external Thunderbolt screen which degraded to 6-bit when a second screen was connected to the downstream Thunderbolt port. The reports also seemed centered around the Intel HD620/HD630. I may at some point pick up a secondhand 7th-generation Intel NUC with an HD620 for further investigation.
WhisperingWind This way, we will disable dithering if it was enabled by default (by clearing the 4th bit of the register) and set the color depth to 6 bits on output (bits 5-7 of the register are responsible for this; 010 - 6-bit output; 000 - 8-bit output).
Did you try setting the color depth to 6-bit in this manner, and if so did the Windows display information report bit depth as 6-bit? This could provide for a fairly easy mechanism.
Did you try setting the color depth to 6-bit in this manner
The first mention of this I found in one of the comments in the Linux kernel:
For Display < 13, Bits 5-7 of PIPE MISC represent DITHER BPC with valid values of: 6, 8, 10 BPC.
ADLP+, the bits 5-7 represent PORT OUTPUT BPC with valid values of: 6, 8, 10, 12 BPC.
As I understand it, this capability appeared starting with the 13th generation of desktop CPUs and starting with Alder Lake P in the mobile segment. I have a mini-PC with a mobile i5-12450H CPU, on which I have performed this switch (Windows 10 22H2).
For the ARC A770, this method does not work, as they use the old register format, where the relevant bits do not switch color depth but instead control dithering.
if so did the Windows display information report bit depth as 6-bit
Switching between 6 and 8 bits was determined using this video: https://www.youtube.com/watch?v=suAR1PYFNYA. Once the player opens, you can pause it immediately at the 0-second mark. At the very beginning, there will be highly contrasting waves in the gradient on 6 bits, whereas on 8 bits, the gradient will appear smooth and free of waves.
WhisperingWind Windows 10 22H2
Could you post exact win10 build you use?
I used Windows 10 22H2 19045.5371, with updates up to January 2015. However, I think switching to 6-bit mode will also work in Windows 11.
But, speaking about my BenQ GL2450 (6bit+FRC) monitor, I can use it comfortably only on macOS with an Apple Silicon M1 graphics card in 8-bit mode; 6-bit on Intel is less comfortable.
However, on my relatives' monitor, the BenQ BL2420PT (6bit+FRC, with flickering), the most comfortable setup is Intel UHD 48EUs in 6-bit mode on the aforementioned version of Windows 10; macOS on Apple Silicon M1 is much less comfortable.
I would recommend experimenting to find what works best for your eyes.
P.S. I also noticed an interesting thing: there is a difference in eye comfort between 60Hz and 59.94Hz on my TV. For some reason, 59.94Hz feels better. I assume this depends on the display and won't work everywhere, but if you see 59.94Hz in the list of available resolutions, try selecting it and see if it feels better. On both Linux and Windows, when connected to my TV, I have both options available. Tested on two different PCs with Intel and AMD graphics cards.