It seems to me that some still do not believe in acceptable 8KX performance on current video cards.
Well, I did a practical study on the difference in load between two different native panel resolutions, but with the same SteamVR SS resolution.
I have Pimax 4K, which supports two native resolutions: 1920x1080 and 2560x1440. (2 million pixels vs 3.6 million pixels, i.e. the difference is almost 2 times)
Actually, I just compared the load on the GPU in both cases with the same resolution in SteamVR Home in the same place.
I think everything will be clear on the screenshots.
In fact, I compared 2 different native resolutions 1080p vs 1440p (2mln vs 3.6mln pixels) for GPU loading with the same SS. As a result, it turned out that there is no difference in load between 1080p and 1440p.
The conditions were clean, the helmet did not even move, the picture is the same, same resolution.
Thanks to @Risa2000, it turned out that SteamVR Home gives the wrong idea of resolution, and, as a result, of loading the GPU.
There is a performance difference between different native resolutions in games.
In the case of 1080p and 1440p, the difference was 15%! (Hellblade)
That is, the loading of the GPU has increased in 1440p mode by 38% compared to 1080p mode.
In 1440p mode, native resolution provides 1.8 times more pixels than 1080p.
In the 2160p mode, the number of pixels increases by 2.3 times in comparison with the 1440p mode.
From this we can conclude that 8KX in native mode will require more than 40% (approximate ) more performance than 1440p (8K +) mode.