Why 8k is more Gpu demanding than 5k?

Why 8k is more Gpu demanding than 5k ?
I mean, they both have the same input resolution, so the Gpu draws the same picture, and the upscaller does his job after, doesn’t it ?
I am asking because, like every 8k Backer, I need to choose between both headset, and maybe it’s better to run a game with ultra settings on 5k, than medium on 8k…


Only explanation I can think of is that upscaling amplifies aliasing artifacts, and you therefore need to minimize those using supersampling before sending to the headset.


One benefit of upscaling is to reduce aliasing, so I don’t get why we need to supersample the image…

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Sampling minus 10 frames maybe why 5k + is getting better small details ? Is the conclusion i come up with but earlyer claims about easyer on gpu were for 5k which is only 5k native were as the 8k is 6 or 8 downscaled then up scaled in head set at 8k but i just read that somwhere so it could be hocum

The additional anti aliasing is why I want the tester reviewers to test the 8k at 5k input resolutions and 5k at 8k resolutions and tell us what an apples to apples comparison for resolution looks likes.

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As I understand despite having the same input resolution the 8k renders at a higher resolution, therefore more gpu demanding.

Yeah but this is the 8k upscaller that does this job…

Not really. tl;dr the upscalar doesn’t do the initial render (aka super sampling).

You’ve got render res, then signal resolution, and finally display resolution. Each frame is first rendered at 6-8k , then downscaled to QHD (at some point distortion correction is done, I’d implement it after downscaling for reduced latency but may reduce image quality), send signal to HMD, upscalar converts the image to 4K (it’s nothing magical and quite simple hardware; it’s simplicity makes it faster), then this is displayed on the panel.

Wait ! Why render each frame at 8k ?


yes, a second time……………………………………

Anyway, the Gpu renders the same frame for both 5k and 8k…

Won’t know for sure until NDA is lifted, but I was under the impression that the final image in the HMD looked terrible without rendering at a higher resolution.

No this is not correct. The input signal (edit: the resolution leaving the GPU is the same) is the same on both. The internal render resolution in the GPU is higher on the 8K than the 5K.

So if the input resolution is the same on both, it should the same load on Gpu…

No. For all of the reasons mentioned previously and in multiple threads. Render resolution != signal resolution. That’s not an opinion, but fact.

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Sorry, I really try to understand you, but i still sont see the difference from the gpu point of view between both HMD…

No worries. I was beginning to think you were just trolling. Maybe these will help:

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5K+ is rendering at 5K.

8K is rendering at 6K or 8K, downscaling to 5K on the PC and then upscaling it to 8K on the headset.

So the 5k image doesn’t/wouldn’t benefit from supersampling? Seems like whatever jaggies that are improved by SS for the 8K would be evident in the straight 5K+ image.

I hope the SS “required” for the “better” 8K image is optional and adjustable. Image tinkering vs game performance is such a personal perception choice.

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I was under the impression that it just didn’t need SS to not look terrible. But no reason you can’t turn it on :wink:

Ok thanks for your reply. Indeed I also found other informations on other threads.

So effectively, it looks like gpu supersample or render frames at a larger resolution for 8k than for the 5k, because sending it to the hmds in 5k in all cases. Still, it seems a bit weird why the 8k needs gpu supersample…But it explains why it requires more gpu power…

I will wait 16 september, but it my opinion it could be more interesting to run 5k+ with higher graphic settings, than 8k with lower graphic settings… We will see :slight_smile: