Replace 2022 Mac Studio M1 Ultra with top Mac Mini M4 Pro

[Alameda]

I haven’t allocated/set RAM amount/limit per app since classic Mac OS. Back then, if the app exceeded the RAM allotment, it would crash. According to Adobe, PS should throw an "out-of-RAM or out-of-memory error” alert.

From the same document:


FYI, 70% of 64GB is ~45GB. 85% is ~55GB.

Photoshop is different from most other Mac apps and you can configure how much RAM it will use. If you assign insufficient memory, it will page out to disk more and performance will be lower.

In MacOS, applications can dynamically increase their RAM use, so I don’t know why Adobe does this, but they do. In a Mac with a lot of RAM, it could make sense to allocate more to Photoshop if you work on massive layered images.

 

[adamjury]

Any thoughts or advice are greatly appreciated.

What are your Settings -> Performance settings?

Which tools are you typically using when performance lags?

Using lots of smart objects, not using any smart objects? Layer styles?

Do you get these lag bursts when not connected to the internet? Is the Creative Cloud app also running in the background?

 

[Analog Kid]

Again, OP has shown their CPU usage is low and that their memory pressure is minimal. Suggesting M4 Ultras and massive amounts of RAM are not addressing the problem.

Adobe is managing their own swap ("scratch" in Adobe parlance) and OP has scratch space on an external drive. I'd look at that drive's performance or consider bringing the scratch disk to the local drive.

 

[ChrisA]

@ChrisA and @Andrey84 -

Thanks for the information. I'm kind of stress-testing as I currently have two files open in photoshop that are 7200 x 10800 px, and each has several dozen layers. As you can tell by the attached screenshot, the CPU an GPU don't seem to be straining too much.

So what it does look like it is an issue of not enough RAM, and maybe also Photoshop settings. Andrey84, thanks for the advice about checking in with the Photoshop forums. I thought I had them set properly (Let Photoshop Use: 34GB, 1 TB SSD connected via Thunderbolt 4 as a scratch disk) but there may be something I'm missing!

View attachment 2472705

If the files are simply open, of course, the CPU is doing nothing. You need to look while the computer is "lagging" to diagnose the reason for the lag. Is it doing a tone of I/O or is the CPU usage at 100%? But the fact that it is idling while it is idling is unsurprising.

 

[ChrisA]

Again, OP has shown their CPU usage is low and that their memory pressure is minimal. Suggesting M4 Ultras and massive amounts of RAM are not addressing the problem.

Adobe is managing their own swap ("scratch" in Adobe parlance) and OP has scratch space on an external drive. I'd look at that drive's performance or consider bringing the scratch disk to the local drive.

If this is true (scratch on extertnal drive), then "swapping" will show up as I/O in Activity Monitor and yes, this needs to be on the fastest storage you have, likely the internal SSD.

But do look at Activity Monitor and very the high I/O rates