4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

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Defox
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4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

Post by Defox » 18 Oct 2020, 06:54

I would like to hear an opinion or even a real experience on the topic of DSR comparing the same 4k DSR on a FullHD monitor versus a real 4k resolution on a 4k monitor.

I asked this question for a long time. On the one hand, the render of an increased resolution and then its downscaling with subsequent processing hides all artifacts, hiding the "fake" nature of computer graphics (aliasing, flickering of textures, loss of small details of objects). On the other hand, on native 4k we get complete information, but at the same time, as I suppose, all the artifacts described above will become visible again and to eliminate them, ideally, 8k resolution output is needed, followed by downscaling to 4k, because even the best anti-aliasing options are not are able to provide maximum reliability and will inevitably blurr the final image.

Unfortunately I have never had real experience with 4k monitors. But I can confidently say that 4K resolution on a 1080p monitor makes a very huge improvement in picture quality. More details in textures, thicker grass, a lot of small details that were not even visible, as well as a very clean sharp image without ladders and pixies. In the case of anti-aliasing, on native 1080p, enabling anti-aliasing (especially in the case of TAA and FXAA) washes the picture a lot, but when you turn on 4k with TAA or FXAA everything becomes crystal clear.

And now I hardly understand what the difference will be in a real 4k monitor, I think I already see a lot of improvements on a 1080p monitor. Is it even worth buying a 4k monitor if I can see a big difference right now, or will it be even better on a 4k monitor?

4k 144Hz monitors are too expensive now, and moreover, 1080p resolution on a 4k monitor will look much worse than on a real FullHD monitor, so I think a 1080p monitor is more versatile. Having 2 monitors at once (FullHD 144 or 240Hz and 4k 60Hz) is obviously inconvenient, and the presence of only one of them will lead me to the fact that I will have to choose either a high refresh rate and play competitive games, or a high resolution for playing single games.

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Re: 4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

Post by Chief Blur Buster » 18 Oct 2020, 11:39

A good way is compare first without upgrading first is 1080p native (non-AA) versus 1080p downsampled to 540p.

This is the 1080p equivalent of 4K native (non-AA) versus 4K downsampled to 1080p.

You’ll see pros/cons of the two methods. Roughly the framerate, but different appearance of AA-like quality vs clarity. This can help guide buying decisions to an extent.
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Defox
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Re: 4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

Post by Defox » 18 Oct 2020, 13:31

Chief Blur Buster wrote:
18 Oct 2020, 11:39
A good way is compare first without upgrading first is 1080p native (non-AA) versus 1080p downsampled to 540p.

This is the 1080p equivalent of 4K native (non-AA) versus 4K downsampled to 1080p.

You’ll see pros/cons of the two methods. Roughly the framerate, but different appearance of AA-like quality vs clarity. This can help guide buying decisions to an extent.
The fact that a lower resolution (which does not correspond to the original resolution of the monitor) looks much worse due to the fact that resampling is taking place, and this is probably known to everyone.

The main question is how much better downscaling of 4k resolution rendering looks on a 1080p monitor and real 4k resolution on a 4k monitor. And unfortunately it will be possible to check this only if there are two monitors of different resolutions, because this is a completely different way of displaying an image and processing it.

Perhaps if, when decreasing the rendering resolution, resampling was not applied, which blurs the image, it would be possible to get something similar. The only option I see is only halving the 1080p image using bilinear resampling and then enlarging it back without resampling. But this is still not the same, since 540p is too small a resolution.
Last edited by Defox on 18 Oct 2020, 13:39, edited 1 time in total.

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Re: 4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

Post by Chief Blur Buster » 18 Oct 2020, 13:38

Defox wrote:
18 Oct 2020, 13:31
The fact that a lower resolution (which does not correspond to the original resolution of the monitor) looks much worse due to the fact that resampling is taking place, and this is probably known to everyone.
You can windowbox it with black bars too (1:1 pixel map it) with the NVIDIA Control Panel feature to prevent scaling. But although it is not a size-for-size comparison.
Defox wrote:
18 Oct 2020, 13:31
The main question is how much better downscaling of 4k resolution rendering looks on a 1080p monitor and real 4k resolution on a 4k monitor. And unfortunately it will be possible to check this only if there are two monitors of different resolutions, because this is a completely different way of displaying an image and processing it.
It's a personal preference.

Another interesting angle (if you have an RTX card) is using DLSS 2.0 as the upsampling method and then downscaling the result again to 1080p. And DLSS 2.0 as the upscampling method.
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Defox
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Re: 4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

Post by Defox » 18 Oct 2020, 14:36

Chief Blur Buster wrote:
18 Oct 2020, 13:38
You can windowbox it with black bars too (1:1 pixel map it) with the NVIDIA Control Panel feature to prevent scaling. But although it is not a size-for-size comparison.
I ended up taking a 1080p screenshot, compressing it 2x using bilinear resampling, then doubling it using the neighboring pixel method (it doesn't blur the image, which ended up making every pixel of the image 4 pixels of my screen). Then he moved back twice as far from the monitor as my normal distance.

The conclusions are controversial. At this distance, I can no longer distinguish between individual pixels. Despite the fact that the image has retained its detail in terms of textures, small details of objects, the density of grass, trees and lack of aliasing, the whole image looks blurry (not much) as if using FXAA (By the way, I did not see such blur in real 4k downsampling. Perhaps a slightly different, better-quality resampling algorithm is used there.). The result is clearly much better than setting the real 540p on a 1080p monitor, because in that case, it is simply an impossible mess of blurry pixels, in which you can hardly see anything.

Then I tried to apply a sharpness filter (analogue of nvidia sharpness) to the 540p screenshot, and at this moment I barely began to distinguish the difference at all! Now, to see the difference, I had to really try to peer or get significantly closer to the monitor (which will no longer be the natural distance of the monitor from my eyes). (I should note that in real conditions the image obtained by downsampling without sharpness filters is very clear, so I'm not sure if a sharpness filter is necessary in real 4k downsampling rendering.)

It's funny, but if this is the whole difference between a 4k matrix compared to a 4k downsampling (to start to clearly see the difference, you need to sit really very close to the monitor), then I don't think it's worth overpaying crazy amounts for a 4k model with 144 Hz, if I ever take such a monitor, it will only be for significantly lower prices than now.

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Re: 4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

Post by Chief Blur Buster » 18 Oct 2020, 17:23

DLSS 2.0 does something similar already as part of what it does.

Also, NVIDIA Freestyle filters and Reshade/SweetFX filters can do a realtime equivalent of exactly what you're doing.

Try testing NVIDIA's Freestyle sharpening filter.
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purplew
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Re: 4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

Post by purplew » 19 Oct 2020, 10:56

I owned a 27'' 1440p monitor for 10 years. Went down to 1080p 24.5'' MAG251RX. Trying 1440p render resolution is literally the same to my eyes as native 1440p monitor.

tldr 1440p and 4k are a meme.

bungles
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Re: 4k resolution at 4k monitor vs DSR 4k at 1080p monitor.

Post by bungles » 26 Oct 2020, 11:37

This very much interests me as well. Longtime lurker btw ;) I have a benq 240hz 1080p and an rtx 3080. Ive played around a little bit with DSR because 1080p tends to be cpu bound and hitting 240 constant frames in games I play like Apex Legends has been challanging and there is not really a performance hit going from 1080p to 1440p. The game does look clearer with DSR on to achieve 1440p in game. Still have to do testing on the performance hit as I just briefly tried it. I do wonder for older GPU's that are also cpu bound like 1080ti's and 2080's if using DSR to push more of the load to the gpu would offset the cpu bound issue for 1080p

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