thanks, that shows just how important prt and new rendering methods like your mssa trick etc will become.4K intermediate buffers take 4x memory compared to 1080p intermediate buffers. You could lose more than 1GB just for that.
4K also requires 2x2 more detailed textures (= 1 mip = 4x memory). Otherwise graphics will look as blurry as 1080p up close. Far away graphics will look better, but only if you have enough memory to stream the textures at (2x2) higher quality. So you need 4x larger memory pools for texture streaming.
When we moved from 720p to 1080p we got 4x memory (for 2x pixel count increase). Now we are moving from 1080p to 4K (4x pixel count increase), but get only up to 1.5x memory. Needless to say, the extra memory is not going to be enough to even reach acceptable quality at 4K. Unless most engines are quickly adapting tiled resources / PRT / virtual texturing.
crazy thing is it sounds like even more reason to have split memory, big slow cheaper pool to buffer textures and faster smaller one for rt etc.
although I fully except that's 'very' unlikely now.