P: Bring back the ability of Enhance to run in the background. (LrC)

The change of Denoise in the Camera Raw engine (and thus its use in LRC) from DNG file creation to 'always on' slider was a nice idea, but so poorly implemented that it can only be a bug. 

It has been implemented so inefficiently that it runs with a heavier load than some modern next gen PC games. 

Example - When applying denoise, it takes about 6 seconds (as before) to complete at 50% value. However, this is where things go wrong: The load does not stop. It keeps going and drawing more and more load until LRC starts to lag. Even when I don’t do anything else, it now keeps the processor at ca. 50% load, RAM at 65% and my GPU spiking between 0 and 10% load for acceleration. As soon as I zoom in to see, LRC lags and skips (its not fluid) and when I touch any other slider there is a delay of 3-10 seconds for an update (to exposure etc), all the while LRC keeps loading the PC and spiking the GPU for acceleration.

It has made the update of ‘always on’ and ‘live’ sliders totally redundant. While this delay and excessive loading may not be a problem for some who are used to not having the ‘live’ update effect, it is for those of us who are and rely on it for showing clients real time.

This is a bug. The feature does not work as intended. Just because it ‘works’ to some capacity does not mean it is functional, hence a bug.

Additionally, there is a noticeable difference in how the new Denoise renders after use – it is far too aggressive, and takes a lot of texture out. The previous version was just cleaner.

Is there any update in the works to fix this issue?

There's a way to work if you need to do Enhance in batch AND do something else.

1. Select the images you need to Enhance and move them to a Collection *
2. Open them in LrD Local or ACR and Enhance them there.

In LrC you can work on other images ( imo better not touch the images currently being Enhanced in ACR or LrD)
When ACR has finished Enhancing do "Export Settings to XMP" or do "Done"
When LrD has finished Enhancing quit the app, LrD will save to XMP automatically.

In LrC read from metadata.
So by doing Enhance in other apps one can work in LrC on other images.
.
Keeping two apps running is possible but not recommended IMO as they might slow down each other given these intensive tasks...it seems still better than doing nothing till LrC unblocks the UI.

EDIT

* I have added a little detail I forgot to mention

I suggest to move the images to a Collection because LrC detects images edited externally only if viewing them.

Collection helps.

@ExUSA: "I have tested with the XMP option on and off (I want it on) and have seen no difference in processing times in Lightroom or using ACR."

An issue that I and others have observed is that, and that Adobe has acknowledged as a bug, after applying Denoise to a large batch of photos, switching photos in Develop takes a very long time and the sliders can be very sluggish until the metadata is fully saved to disk.  These symptoms probably don't affect the time it takes to compute Denoise (either individually or in batch).

@johnrellis I have tested with the XMP option on and off (I want it on) and have seen no difference in processing times in Lightroom or using ACR. I have somewhat minimal hardware (M1 Mac mini with 16GB of RAM and a 2019 Intel MacBook Pro) so that may be the bottleneck.

I migrated from Classic, I work locally in the new version.

@kostafotograf: "I cannot work with images after batch-denoising now. They need 20 seconds to load and manage the data, and when they load -- features like copy-pasting settings from a previous photo are broken, as Lightroom re-does the whole denoising process (?!) (wasn't it already analysed in the batch?!)"

Have you enabled Catalog Settings > Metadata > Automatically Write Changes Into XMP? There is a severe performance bug with that setting and Denoise:

https://community.adobe.com/t5/lightroom-classic-bugs/p-automatically-write-changes-to-xmp-can-t-be-used-with-denoise-on-large-numbers-of-photos/idi-p/15393188

After disabling that setting, performance is usually good.

Denoise on M1 MacBook Air is incredibly slow now.
My workflow involves flagging images, denoising and editing.

I cannot work with images after batch-denoising now. They need 20 seconds to load and manage the data, and when they load -- features like copy-pasting settings from a previous photo are broken, as Lightroom re-does the whole denoising process (?!) (wasn't it already analysed in the batch?!)

When you copy over ONLY the settings for color and light -- the image needs ANOTHER 20 seconds to recompute, on the top of the additional 20 seconds needed to load it.

It's as if every single operation besides a slider causes recomputation of the image.

This is ABSURD. I cannot go through 10 photos. I would've edited 110 by now.

Switching back to a previous version, and hoping Capture One develops a better alghorithm. This is absurd messing with professional workflows that people pay big bucks for. 

I downgraded to the previous version of Lr and I'm back in business 

If that were the case, Adobe would be burying a product that many professionals still enjoy using. The slimmed-down version, Lightroom (Cloud), is completely unacceptable for demanding workflows.

@Alwaysheathbar wrote

'when I was signing up it was expressed to me that Lightroom classic was getting phased out "sometime soon"'

I don't know who expressed that to you, but I don't think there is any truth in it at all.