I have used M27UP for few months now. I usually use 4k 160hz mode for everything else than CS2 where 1080p 320hz is a great deal.
But how it actually works and how is this achieved? In theory it makes sense when you divide 4k resolution by 2 it's 1080p and 160hz goes up 2 times. But in practice GPU sees these 2 modes as a different monitor, which also explains why custom resolutions in Nvidia control panel only show up in 1080p/320hz mode but not in 4k/160hz and other way around.
Well I was toying around in Nvidia control panel and I was able to pull out 1600x1200 (4:3 aspect ratio) in 320hz on 1080p/320hz mode enabled. I have seen this resolution only when I used 1440p 240hz monitor before, so I tried more and was able to make 2048x1152 16:9 aspect ratio to work on same mode in 320hz. On Nvidia DSR is DISABLED and scaling is forced by Monitor so GPU just sets the resolution, monitor does the rest.
That got me thinking; how and why it can go further than it says in paper?
Im not new to "overclocking" monitor to achieve higher Hz on native resolution, but going actually over the native resolution of the dual mode and keeping the same Hz is new to me.
I would like a deep technical explanation why and how it works.