Green dots all over at 4K 60 Hz

Inelastic · August 26, 2019

On 5/25/2019 at 3:13 PM, WiiMAN said:

So update time. I spoke with NVIDIA and we were able to get 4K 60 Hz working. I had to change a setting in NVIDIA Control Panel (I’ll tell you what it was when I get back to my PC, forgot what it was). But we couldn’t get HDR working, having it enabled on the TV makes the TV say “Signal not detected”. Neither NVIDIA or Samsnug support have been able to figure out the cause...

funnily enough, if HDR is enabled before turning on the PC and then I turn it on, I can access the BIOS normally. Looks a bit stretched but it’s viewable with no green snow. The Windows loading screen also shows up normally. But as soon as I get to the Log In screen, the TV loses the signal, often times locking up the PC as well and forcing me to disable HDR and restarting the PC

That happens to me occasionally on my Sony x900F. I'll have the enhanced hdmi setting (the 2.1a support that allows for HDR) turned on and everything works fine, then all of the sudden I'll turn my pc on and I get that same message once it goes to the Windows login screen. Turning off that setting on the tv brings the image back. I used to fix it by doing a factory reset on my tv, but now I can usually get it back by fiddling with the display settings, changing the refresh rate to 30hz to be able to change the color output and depth to something else.

Kisai · August 26, 2019

On 5/25/2019 at 1:13 PM, WiiMAN said:

So update time. I spoke with NVIDIA and we were able to get 4K 60 Hz working. I had to change a setting in NVIDIA Control Panel (I’ll tell you what it was when I get back to my PC, forgot what it was). But we couldn’t get HDR working, having it enabled on the TV makes the TV say “Signal not detected”. Neither NVIDIA or Samsnug support have been able to figure out the cause...

funnily enough, if HDR is enabled before turning on the PC and then I turn it on, I can access the BIOS normally. Looks a bit stretched but it’s viewable with no green snow. The Windows loading screen also shows up normally. But as soon as I get to the Log In screen, the TV loses the signal, often times locking up the PC as well and forcing me to disable HDR and restarting the PC

Green sparkles/lines is always an indication of a cable/signal issue due to bandwidth/errors. The thing that should have been checked is the monitor/TV's HDR setting on that port. Some screens only support 4Kp60 HDR over DP 1.4 or HDMI 2.0a, and even if the cable is correct the data sent to the graphics card via EDID might not match with what the driver expects.

Also note "stretched screen" at BIOS indicates that it's might not be running in UEFI mode. UEFI will allow the dedicated video adapter to operate at 1920x1080 at boot, where as legacy mode will initialize it at a 4:3 ratio at a much lower resolution.

The most common reason for green sparkles or the entire screen going green (or red) is that the cable is too long and the copy-protection handshake is failing after previously succeeding.