Best Macbook Pro specs for focus stacking (auto-blend layers)

[hajfimannen]

I am in the process to upgrade from my current Macbook Pro (Intel i7) to one of the new M4 Macbook versions.  I regularly focus stack multiple mages for macro using Auto-blend layers.

How should I confugure my new Macbook Pro in order to speed up the process in Photoshop?

Is this a RAM dependet task or more CPU focused?

[D Fosse]

Almost everything in Photoshop is I/O-limited, in other words scratch disk. Especially something like this, where you will presumably have many files open and processing at the same time.

Photoshop's memory requirements vastly exceed the amount of RAM you may have installed. So the heavy lifting is in the scratch disk, with RAM mostly being a cache to the scratch disk. You should have around 500 GB - 1 TB free disk space.

However, with Apple silicon there's an additional consideration: The GPU uses shared system memory. This is important, because the GPU can use a lot and could potentially compete with the RAM allocation in Photoshop preferences. For this reason, the rule of thumb is to double the amount you would normally need. 64 GB should be considered minimum.

Also, be very careful to not set the PS allocation too high! The default is 70%, but if you get problems be prepared to dial it down a bit. This depends on your file sizes, how many files you have open, and the number of history states.

[hajfimannen]

Thank you for explaining the many resources needed to keep PS happy. 

Could you elaborate slightly on the scratch disk situation. 

Would PS only use the internal hard drive for this? Or can it use free space on a separate SSD that I hook up?

[D Fosse]

I would strongly recommend that you put your scratch disk on the system drive. You set this in preferences and while it's possible to put it on an external drive, it will be slow and inefficient. And it will need to be connected at all times while using Photoshop, so your laptop stops being portable.

It goes to the system drive by default.

[hajfimannen]

Once again, thank your for taking your time and sharing your knowledge. 

I feel much more confident going forward on ordering a Macbook.