There has been a bit if confusion around this bug fix. It’s not for using the Denoise slider to set the amount before applying it, which some people wanted. It’s about recalculating when applying to multiple images.
The current behavior has been modified, and now we avoid recalculating the result.
In both Lightroom and ACR, the Denoise amount cannot be adjusted before applying it. This is a regression from the previous preview UI where the amount could be changed before applying Denoise. This means that Denoise must be applied before changes are possible, and the result must be...
I was quite stunned to see how many complaints there were on the Adobe forums about the new no DNG Denoise process introduced in June. Some wanted the old way, to see it before applying it. Then you had the ones who said you can't judge at 240% or whatever size it showed it so they were happy with that change. Also they couldn't choose the amount they liked for denoising multiple in. Do your first one and then sync. What really surprised me was some wanted the DNG back.
I'll never miss the the old method. No DNG. Tweak the Denoised file as many times as you like at any viewing size. I waited for months for this. I had hoped we would get the Numeral Engine back again. Perhaps at v15 as 14.5 will likely be the last big one. Adobe does major updates about every two months.
Yeah, I'm fine with the new denoise. It was confusing at first though, it was like the AI denoise got demoted or something. But it is good.
As for the GPU use to generate 1:1 previews, that is just for high-end computers, and high-end computers don't need it because they are fast enough to permit editing while preview making goes on in the background.