The times that i manage to put it in game mode that doesn't crash the TV, which then starts to show 8k native resolution, it simple doesnt accept clicking it. You try change the resolution to 8k via nvidea and windows it simply reverts to 4k. Not once has the Samsung UI in the top right corner showed 8k.
Ok, heres my fix. use Custom Resolution Utility to 'reset all', then 'restart'. Set the resolution to 4k 60hz. Once there put on game mode (which enables Input Signal Plus). Once monitor is at 4k 60hz with input signal plus on, 8k Native res should appear. I clicked enable 8k resolution with 4:2:0 10bit (nvidea control panel). It didnt work 5 times, keep trying, and randomly it works. The key seems to be YCbCr420 mode (4:2:0). GLA - props to Wickfut for helping.
You don't need to install the custom resolution software to enable it. You just need to do it the moment you've updated the GPU drivers. If you restart the PC it won't work and you'll need to fresh install of the drivers again.
Still waiting on Samsung and Nvidia to get their finger out .
These are the settings that it works for me. Just latest NVidia drivers for the 3090 RTX.
NB: it only works for HDMI 4...
Q900T should be in Game Mode (“Hi Bixby, Game Mode on”)
The TV/PC remember the settings after power off/on.