Abysmal 1440p Performance

So I've been working really long time on my Fallout 4 and Witcher 3 presets. Only now that my 1080p monitor died and I bought 1440p one they are practicaly unusable...

The presets uses : SurfaceSharpen,YACA,Tonemap,LiftGammaGain,FilmicPass,LightDoF_Far,AmbientLight,DiffuseGlow For Fallout 4
Technicolor,FilmicPass,AmbientLight,LiftGammaGain,CrossProcess,SMAA for The Witcher 3

On 1080p there was a minimal FPS hit, if any on GTX 1070. But now in 1440p, the Fallout 4 for example, runs stable 60 FPS, until I turn on ReShade, then it's 45 FPS.
How does that make any sense ? I'm not even running demanding shaders, the hardest hitting one is Ambient Light, which had like 1-3 fps hit at max, before.
Is there something I'm missing regarding 1440p ? Is there any way solve it ?
I would appreciate any help with this.

Absolutely res will have an effect on Reshade, scaling with as the res goes up. Aside from processing larger buffers, many effects are based on resolution, and they too will require more work.
Click on the last tab with the stats in-game, and look at the ms load each effect is having, you'll be able to see the most demanding ones right away.

Performance of pixel shaders almost linearly scales with amount of processed pixels.. 2x more pixels to process, 2x render time. 1440p has 1.7778x the amount of pixels of 1080p, hence the shaders need 1.7778x the time to render (+ the game also needs more time). Generally, the higher you get, the more unstable the fps get.

@Martigen I know about that, that's why I'm saying that Ambient Light is the only demanding shader I'm using. And SMAA only in 1440p, wich destroys The Witcher 3's framerate.
@Marty McFly That makes sense, but even if it was 2x the pixels, which isn't, 1440p is about 230k pixels more than 1080p. With 1080p being 2,1m pixels, I tought that it won't be hitting as hard as it does, it surely takes more than twice FPS compared to 1080p.

I might be wrong with my ''calculations'' but, it still eats alot more than it should, I'd say.