More tools, less Performance .....

@rayek.elfin 

Actually you did: "possibly a rewrite from scratch".

Anyway, the point I'm trying to make is that lots of people have claimed that Photoshop is "bloated" or "not optimized", but nobody has ever identified specific performance problems caused by that alleged bloat.

Yes, there are bugs, obviously. All software has bugs. Yes, there are small details that you might wish were different. But you get the job done. What I mean is basic architectural problems.

The fact is, Photoshop is rock solid. I can honestly say that of all the software I have ever used, Photoshop is probably the one that has caused the least problems for me. It never crashes or freezes, no matter what I throw at it.

All you need to do is give it the right environment and enough resources. That's true for everything, even people. I couldn't do my job if I didn't have the right equipment to do it.

Note that I didn't write a complete code rewrite. Nor did I state that that rewrite should take place all of a sudden in a short amount of time. 

Blender has had two rewrites and because of those Blender has catapulted into the stratosphere, turning it into a market leader (even if it is open source!). Cinema 4D had its core updated over a number of years (which did lead to a slowdown of new features introduced). PhotoLine was restructured and its core sped up over the last decade, new core features added, and the GUI completely overhauled.

I mean: Photoshop hasn't even seen any core improvements in how it deals with 16 bit images (the so-called 16 bit mode that actually is a 15 bit +1 bit mode) since when it was first introduced way back in 1991(!), still no layer support in indexed mode or 1bit mode, the max image size limit of 300,000px, still only one layer mask and vector mask per layer, no layer instancing, only one image mode option in Curves and Levels and other colour adjustments, still no additional procedural noises and patterns (clouds still have no adjustable parameters, sigh), and so on and so forth.

It took the dev team --what?-- 10 years or so to add a Curves window that is scalable! And sadly the Curves dialog and functionality could have had tons of real functional improvements...

And there are so many more things that can be improved in Photoshop's core design. The layer stack is looking old in the teeth. The 3D features were removed, never to be seen again. 

Still waiting after 30 years for some improvements in any of these areas.

Ah well, I will shut up now. It is what it is. Sorry for the rant.

@rayek.elfin 

The "rewrite from scratch"-notion was debunked already 25 years ago, and this is likely even more true today when software is orders of magnitude more complex. This is an internet classic:

https://www.joelonsoftware.com/2000/04/06/things-you-should-never-do-part-i/  

Photoshop is a power tool, and like all power tools it needs solid support to stand on. It's as simple as that. The hardware needs to be up to it. There are plenty of simpler consumer-oriented image editing apps that may in some circumstances be more appropriate and work better.

I don't entirely disagree with you @D Fosse , but there are instances when Photoshop gobbles up memory like there is no tomorrow and other image editors use far less memory compared.

For example, I have three images:

• a 16bit greyscale image
• an 8bit RGB image
• an 8 bit normal map image

All are 32.000 by 16.000 pixels

Photoshop

The 8bit image is loaded first. The 16bit grey image is placed as a smart object. So is the normal map.

Memory usage

Private Bytes 24,811,532K  |  Working Set 16,818,216K

PhotoLine

All images are loaded as-is, with the 8bit RGB file loaded first. PhotoLine doesn't require smart objects to maintain each layer's bit depth, resolution, colour space, image mode, etc. All data are maintained by default on a per-layer basis.

Memory usage

Private Bytes 9,144,004K  |  Working Set 8,522,088K

With the same layer stack, images, effects, and adjustment layer mask, PhotoLine draws on average 50% less memory than Photoshop. The developers of PhotoLine are known to optimize their app in this regard.

Affinity takes up as much memory as Photoshop with this task. More, actually. In short, both Photoshop and Affinity could be optimized further in how they utilize memory.

As far as batch processing is concerned: Photoshop is slow --dead slow-- compared to other options (including PhotoLine). It can take ages for a batch to complete when other apps finish in a 10th of the time, mainly because Photoshop wants to open each image in the view. This could be radically optimized in my opinion.

What is also frustrating at times is that Photoshop refuses to release memory when files are closed. You @D Fosse already mentioned this. Affinity shares this (at times) inconvenient behaviour with Photoshop. PhotoLine just releases its memory nicely. Well, at least it is possible to force Photoshop to release memory by holding down ALT and then choose the Help-->About option... 😉

Lastly, Photoshop does take up an inordinate amount of memory just for the base application in my opinion.  I suppose the legacy libraries and developer addons throughout the years have turned it into memory pacman 😄 The balance between functionality vs memory usage seems inbalanced towards the latter.

Even Blender 5, which features FAR more functionality as a whole than Photoshop, takes up 800MB working set memory (that's with many addons loaded!). PhotoLine's executable asks for a mere 437MB. Compare with Photoshop's 3,6GB and I start wondering why so much memory is required for the base application, because its feature set is good, but it's still an image editor.  Affinity takes up as much memory for its core app, but that can be explained away since it combines three apps in one.

Sure, PhotoLine misses the AI functions (I hear you crying out loud); yet Krita, which offers a similar feature set, and has a good AI plugin, combined asks for around 510GB of memory... 

I know, I know: comparing apples and pears and oranges. Still, Photoshop strikes me as an app that could benefit from a code cleanup. Possibly a rewrite from scratch. We all know that its core contains legacy outdated functionality (16bit mode, destructive masking/channel operations, limited layer masks, limited image dimensions, etc) which haven't kept up with the times. 

All that said, context remains important. Loading those three images in Blender's compositor leads to it devouring 39GB of memory... Photoshop looks alright compared 😄 

That number is irrelevant. The instant you start working on the image, memory consumption quickly increases up to the limit you have set in Preferences (by default 70%), and it will stay at that level throughout the session. This is normal and expected.

On startup, Photoshop allocates memory based on expected "normal" needs. It goes rapidly upwards from there.

This is not because Photoshop is not "optimized". It is because raster image editing moves massive amounts of data around, and all that data has to go somewhere. In fact, the total memory requirement goes far beyond any RAM you may have installed, so temporary working data are written to disk, aka the scratch disk. Think of the scratch disk as Photoshop's main memory, with RAM as a fast access cache. Photoshop never "runs out of memory" because the scratch disk does the heavy lifting.

But this is why it's important to not set the memory allocation in preferences too high. 70% is usually optimal, but if you have less than, say, 32 GB RAM installed, you may want to dial down the allocation to avoid choking the rest of the system.

Each history state potentially adds the full nominal, uncompressed file size. If you want to reduce the memory/scratch disk footprint, reduce history states, if necessary all the way down to 1 or 2. In addition, some of the newer advanced functions use the system pagefile for temporary storage, particularly those that are AI based and executed in the GPU.

By design, Photoshop does not release memory when you close a file. That memory is reused and recycled. This is what makes batch processing possible. Requesting memory from the OS for every file is much slower.

Bottom line: Photoshop, as professional-grade software, is highly optimized for speed, efficiency and heavy-to-extreme workloads. This is an application that can handle anything you throw at it. What it is not optimized for, is limited hardware resources. That is the user's responsibility.