Reshades FPS hit at high resolutions

I've noticed that when i use anything over 1440p Reshade seems to have a massive performance hit thats roughly the same for every game. I've been using downsampling quite a bit since AMD finally got around to implementing it but even at 3200x1800 the fps hit is pretty large if i turn reshade on.

Is this just something that is bound to happen because of how reshade works? It seems like nothing else has half as much on an effect on fps as Reshade at large resolutions from my experience. If this is just due to the nature of how Reshade does its magic what happens when these resolutions become the norm, or will sheer brute force from newer graphics cards counter it?

well compared to 1080p, 4K resolution is 4 times bigger which means that reshade has a fps hit of 4x more per shader if i'm not wrong.

Sounds like a bottleneck.

crosire wrote: The only explanation right now I have is the following: ReShade has to create a bunch of textures at the size of your resolution and does copying jobs between those each pass. The bigger the resolution, the slower this can get, but there is no good way around (I tried all kinds of solutions, replacing the backbuffer altogether instead of copying etc.).

At the risk of sounding like I don't have a clue what I'm talking about (er, and I don't) -- could compressing them help, reducing copy bandwidth? Of course, this has its own overhead but perhaps one is less than the other.

crosire wrote:

klotim wrote: well compared to 1080p, 4K resolution is 4 times bigger which means that reshade has a fps hit of 4x more per shader if i'm not wrong.

And this. 4 times the hit is quite a lot. And since some shaders are very demanding, this quickly goes under the roof, meaning you need 4 times more GPU power to compensate.

The gaussian options is excellent for this, is it not possible to do this for other shaders?
#define BloomTexScale 2 //[0|1|2] //-0 = Off, 1 = 1/2 Resolution, 2 = 1/4 Resolution.

1/4: 1080p perf hit compared to 4x performance hit at 4K (value 0) right?

Maybe were just what you answered but after all the option is available for gaussian?

crosire wrote: ReShade allows rendering effects in lower or higher resolutions, but not many shaders written for it make use of that feature yet. Gaussian being one of the few.

Is the slowdown Reshade's texture copying etc on code running on the CPU or the GPU? I'm guessing it's CPU, in which case can that shit be multithreaded? (disclaimer: again I don't know what the heck I'm talking about).

Otherwise I imagine the impact is just going to reduce over time as more powerful hardware comes out.

Maybe the problem will run in parallel to some extent though, that was what i was getting at. The performance impact from going up resolutions without reshade isn't anything like the hit you get from reshade over that larger resolution, which is understandable considering what its doing, but i thought we might eventually run into performance problems when say, 4k is the norm.

But then again I don't know what I'm talking about, this is just my attempt at articulating what i thinks going on, without any technical knowledge.

Its really only a problem for me in games with no aa so far, which are thankfully more of a thing of the past. No AA in alien isolation was criminal though.

crosire wrote:

Martigen wrote: Is the slowdown Reshade's texture copying etc on code running on the CPU or the GPU? I'm guessing it's CPU, in which case can that shit be multithreaded? (disclaimer: again I don't know what the heck I'm talking about).

No way I would do that on the CPU, that would be insane. Everything runs on the GPU. Almost nothing ReShade does is CPU bound.

Oh cool

crosire wrote:

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No way I would do that on the CPU, that would be insane. Everything runs on the GPU. Almost nothing ReShade does is CPU bound.

Can you make optimizations for nvidia/amd cards? It could be possible right?

crosire wrote: ReShade allows rendering effects in lower or higher resolutions, but not many shaders written for it make use of that feature yet. Gaussian being one of the few.

Which are the other shaders that use this?