JTL We are on the same page I think...I may have just expressed it wrongly. The laptop panel doesn't have built in dithering instructions or blue light/contrast/brightness whatever etc like a desktop monitor can so I called that a "dumb panel". As I understand it the panel's pixels have to "dither" to get the "super awesome vibrant" colors and thats what I meant by saying the gpu is making the panel dither. I understood the gpu is making it happen.
JTL Nearly every BIOS screen I have seen is on 100% brightness with no ability to reduce it so I can't stand looking at them just due to that...it's blindingly bright and hurts on anything but a super old dim CCFL. A 2014 Thinkpad I got for testing did surprisingly allow brightness controls to work in the BIOS but an update ruined that.
What does that mean? Why in the world would a text only, pre OS utility be dithered? Does that mean its just hardwired into the gpu and whenever a computer is on its dithering regardless of what is displayed? I had some hope it was dithering because instructions in the OS/drivers were telling it to which would mean it might be possible to turn off. If its in firmware before the OS and drivers even get loaded how could we even affect it?
deepflame Teradici (a company that makes display over Ethernet extenders that use image compression which dithering interferes with) claims that the 10-bit color option on certain AMD graphics cards can disable dithering. So that's another datapoint.
This could be huge as an easy DIY test to see if dithering is or isn't an obvious problem. Do you have any more info on what gpus? There isn't any detail. I see there are linux instructions there which was a nice surprise as I thought "yeah it probably only works on Windows". If this would work on AMD Ryzen/Vega laptops etc it would be an easy test as there are a couple at Best Buy I could try in store if this Catalyst Center thing is normally installed...but they have locked down internet so no installing new stuff there.
Do you know if you can enable 10-bit monitor support, thus turning dithering off, on a Linux system with an AMD GPU/APU somehow? I could also live boot linux in a shop and try that as well. Worst case I would buy an AMD laptop and just return it if it didn't work...but I guess I need to know what GPUs/APUs this works for first. Does Nvidia have a similar process since there are a lot more Nvidia models out there to test?
hpst I do plan to test this after I get the same/similar laptop as @deepflame after the capture card. Just a few more things to sort out with my desktop before I order it, nothing to do with you.
I'll write you a summery email tomorrow.
JTL Well if Catalyst isn't used anymore as you said its likely this is old news. I was hoping I could either with a swtich or config file do the 10-bit enabling on a modern system and test it. Excited for nothing I guess since a 2008 year Thinkpad being usable isn't really helpful to me even if it works on that.
JTL I have two of these Lenovo W500 now and one has gone bad. I think the reason was that I installed the Eizo drivers that came with the ColorEdge display I got. Now it even dithers on boot which the other good one does not.
I already tried to remove the battery and to reset the CMOS but I am not sure if it really helped. It may be that the Windows software made it bad again after boot.
Will test this again when time permits. ( I learned the hard way that color calibration has a big impact on dithering. this just shows me that colors and color depth play a big role in this. )
Just to let you know that there may be some things to look out for.
andc i suspect that notebookcheck pwm reviews are highly untrustworthy.
i have read several reviews that dont match.
Also my Xperia XZ 2, in notebookcheck, says it has pwm until 28%. But i check that it has also beyond that point almost until 100% with my canon 550D at 1/4000. I also use a 1.4 aperture lens, so i can i have light to check it.
Above the 28% brightness what happens is that the phone seems to go to a higher pwm frequency.
Until 28% is 2khz, above that seems to double it.
I am waiting for my oscilloscope to arrive to check it properly.
So maybe some displays, change PWM frequency depending on brightness.
It would be good to know if all the Notebookcheck's reviewers use the same gear and procedures to test for PWM and what the max frequency that can be checked is. I've also seen different results on almost the same machines, but I thought that this is related to different panels or internal components. Actually such information should be provided by manufacturers, the same way as refresh rate, contrast, since it becomes a rather important factor and isn't so easy to test properly.
andc You record on your microscope with HTC 10 at 120 fps?
The leds change at different frequencies. For instance if you could record at 2000 khz you could watch them flicker at a different rate, if they would have pwm. For 120fps they change differently, if you record at 60fps also differently.
Maybe for the eye there is a worst range.
