Photoshop Using 75GB RAM – Is This Normal?

Two important things about evaluating memory usage on an Apple Silicon Mac…

The first point is that the Memory column does not represent installed RAM (unified memory). It represents the total memory management system. It’s easier to evaluate what’s really happening with memory if you un-hide some of the columns that are hidden by default, such as Real Mem and VM Compressed. For example, in the picture below, you see that for Photoshop, the Memory column reports 2.31GB (the total), but Real Mem reports only 239.1MB (actual memory used on the RAM chips). The rest of the 2.31GB is compressed or swapped. Why just 239.1MB of real RAM? It’s because I haven’t opened any documents yet. Similarly, the Memory column reports 10.80GB for Adobe After Effects, but when you look at the Real Mem column you see it’s really only using 732.2MB of real RAM at the moment and a lot of the rest is compressed. macOS and apps constantly shuffle data in and out of these states to use real RAM on whatever data needs to be handled the fastest at any moment.

By the way, this is why it’s easily possible to see a Memory value that exceeds the total RAM in the Mac — it’s also counting how that memory is being shuffled outside straight RAM, such as compressed and swapped memory. On any Mac, if you total the values in the Memory column for the hundreds of processes running at any time, under heavy workloads that total can exceed the amount of installed RAM, for the same reason: It’s counting data stashed in multiple forms of memory in addition to the RAM chips. (If you wanted to try this exercise, just select all the rows in Activity Monitor and copy them to your favorite spreadsheet.)

Side note — I don’t think any of these columns accounts for the memory usage of the Photoshop scratch file, which is sort of a Photoshop private virtual memory system. 

The second point is, to fully understand memory usage, when showing a screen shot of the Memory tab in Activity Monitor, always show the bottom, where the Memory Pressure graph is. This is critical. As explained above, the numbers you see in the Memory column are not actually just about the RAM chips, they are all relative to the total memory management system, all of the different ways macOS can cope with large memory requests. The Memory Pressure graph is important because it shows you the “big picture” of how well the complete macOS memory management system (real memory, compressed memory, swap memory, purgeable memory) is coping with demand. When the graph is green, then it doesn’t matter if some of the numbers look scary, macOS is actually handling all memory requests with no problem. If it stays orange or red most of the time, again it doesn’t matter what the numbers say, the memory system is overloaded and the next Mac should be ordered with more Unified Memory. (Mine is usually green, it’s only yellow here because I have a bunch of major apps open at the same time.) 

Neither of those points answers why Theii is seeing 75GB usage for Photoshop. That does seem unusually high, unless the documents are large or have many layers. However, in the forums here we have seen various threads posted about macOS reporting the memory usage of Adobe apps to be far beyond the RAM installed in that computer. It has often been reported for Lightroom Classic; although I have not run into that, I have had it happen in Premiere Pro where there was one project file when Premiere Pro memory usage would climb until it wanted over 150GB of RAM (on my 32GB computer), and then froze up the Mac when its memory management system decided it was out of options (real RAM, compressed RAM, purgeable, and swap are all maxed out). I don’t know what causes that, but many posts here show that it does happen, whether it’s a memory leak/bug on the Apple side or the Adobe side… But when users post about excessively large memory usage here, we rarely get a good answer. Hope we get a better answer this time.

I am puzzled as to how your Mac reports 75GB of RAM usage on a system that you say has only 64GB of RAM. I use Windows so I don't know the background of the  Mac activity monitor and how it calculates process memory, but it does look strange.

Photoshop will always use the RAM allocated to it and will alway use scratch disk space regardless of how much RAM you have. That is normal (I have 256GB RAM here and scratch disk use can run to several hundred GB). Raster editing involves moving around a huge amount of data and that data needs to be stored for every layer and every step in history. Scratch disk is not a fall back when RAM is used up, the scratch disk is the primary storage space for that data and RAM is used for fast access to parts of that data.

Can you go to Photoshop's System info, click 'Copy' and paste the info here.

Dave

Aleke's advice is excellent.

While looking at optimizing Ps performance, check the section on Photoshop Compositing, especially multithreaded compositing and GPU-accelererated compositing.

Can you capture the screen post-crash?

Hi @Theii 👋 Welcome to the community! Thanks so much for the detailed info on the issue.

There's a new version of Photoshop (26.4.1) available. Could you please update and test it to see if it resolves the problem? If you haven't already, please also check out this handy guide for optimizing Photoshop performance: Optimize Photoshop Performance.

Thanks a bunch!

Alek