Poor Photoshop writing performance of PSB - files

Unfortunately, save speed is probably not significantly improved by upgrading to a more poweful computer. If you look at macOS Activity Monitor during a big PSD/PSB save, it does not come close to saturating the storage speed or all of the CPU cores. Apparently there are some bottlenecks associated with getting the data into the state where it can be written to a file (I don’t know the technical details, though D Fosse hinted at some of them).

A new Mac Studio is potentially many times powerful than an i5 iMac, but it can’t achieve that in all areas. Where you see the most dramatic performance improvement is in software that can fully use all CPU cores, GPU acceleration, and storage speed. These tend to be video editing, visual effects, and 3D applications because they always have thousands of frames or vector objects to constantly re-render, so they can hand those off to all the CPU and GPU cores.

For editing a single still image document in any application, a lot less of a Mac Studio gets used. An image editor like Photoshop has limitations in how much it can spread out the work to more cores. The additional speed of the Pro/Max/Ultra variants is essentially all about adding more of the same thing: More CPU cores, more GPU cores, more encoders/decoders…but a very important point that many Mac users miss is that the frequency of one CPU core is about the same from the base M1/2/3 processor all the way up through the Pro/Max/Ultra. So if an application is only able to employ one or two CPU cores for an operation, an M1/2/3 Studio Max/Ultra is not going to be that much faster than a base M1/2/3.

Many Photoshop users have asked about slow save speed before, so I think Adobe is aware of the problems. But it is not clear how much they are working on it. I thought they had posted about some minor improvements in save performance recently, but I can’t find where those are in the public release notes.

A flat, 3GB PSB should normally save uncompressed in a few seconds - but layers are a big variable. 40-50 seconds doesn't sound normal at all for an uncompressed file, but for a compressed file that's about what you can expect. Again dependent on layers.

Writing to disk is a very small part of a save. Most of it is encoding, packaging the data according to file format specification, which is done in the CPU. That's why compression takes so much longer.

Edit - I had a flat 3GB uncompressed PSB handy, and it saved in about 2 seconds. Took a bit longer to open, though.

@minzi0815 

I've moved your post from Creative Cloud Desktop to the Photoshop forum for you.

Jane