Mac M2 Pro or M2 Studio Max for best Lightroom experience?

Is LR CPU or GPU intensive or both? RAM intensive?

By @Scott Dobry

The answer is “yes” and “it depends” (I explain that below). Also, the answer changes over time as the developers find more ways to accelerate different areas of the application. For example, GPU acceleration was recently enabled for export, and more recently, the Apple Neural Engine was enabled to help speed up AI Denoise.

CPU: Single-core performance and having more CPU cores benefits overall operation and preview generation.

GPU: More GPU cores benefit the GPU-accelerated parts of Lightroom Classic, but currently, only some parts are GPU-accelerated such as the Develop module, AI features, AI Denoise and exporting (GPU acceleration saves the most time during large bulk exports).

Unified Memory: Having more helps everything, especially the GPU, but after you reach the amount you need (which for most people is between 24-64GB), paying for more makes no difference.

Unless the M4 is some kind of breakthrough (probably not), even if Apple announces something it might not be that much better for Lightroom Classic than the M2/M3. So the real benefit of an M4 announcement might be to push down prices on the M2/M3 models.

For many people who need a Mac desktop for Lightroom Classic, the base Mac Studio is a nice balance between price and performance.

OK, now for more details:

For example, in LR on a large 1000+ image job (Canon R5 raw images) the preview renders in Library mode can be frustratingly slow. The thumbnails are there but they can be soft/fuzzy for 1 and up to 10 seconds before "blooming" in to sharp focus…

Perhaps I'm lacking a "setting" in preferences (camera raw cache settings or GPU setting)?

By @Scott Dobry

Currently, preview generation depends totally on CPU performance. GPU and memory are not major factors. Also note that “previews” means viewing images outside of the Develop module. Inside the Develop module, the preview can use GPU acceleration, is always rendered from raw at the highest quality, and is cached in the Camera Raw cache, not the previews cache.

CPU performance for previews works out like this:

Faster single-core CPU speed is better, of course. But in the Apple Silicon range for Macs, single-core speed is roughly the same across the line. So getting an M2 Max or Ultra does not get you noticeably faster single-core speed than a base M2. To get more single-core speed, you move up to an M3.

More CPU cores can benefit previews, and this is where the upper Mac tiers help. The 12 CPU cores on an M2 Max (and the 24 CPU cores on the M2 Ultra) should be able to process more previews in parallel compared to an 8-core M2 mini, although it might not be 1:1 (having 1/3 more cores might be not quite 1/3 faster). But to make this happen, make sure Generate Previews in Parallel is enabled for Lightroom Classic, because if it’s disabled I think Lightroom Classic won’t apply all available CPU cores to preview generation.

Also, some of the new LR AI masking features are very slow.

By @Scott Dobry

Masking and AI masking depend heavily on GPU performance, which depends on the number of GPU cores and amount of available Unified Memory.

Your Mac mini has 8 GPU cores. Compared to that, the 30 GPU cores in an M2 Max will speed up anything that’s GPU accelerated, so there should be a noticeable improvement in general Develop performance and AI masking. The most directly observable improvement benefit is in AI Denoise, where doubling the GPU cores generally halves AI Denoise processing time.

The amount of Unified Memory affects GPU performance because the OS and GPU both draw memory from that pool. On a Mac with 8GB (and maybe 16GB), after the OS, Lightroom Classic, and other processes take the memory they need, there might be too little memory left for effective GPU acceleration. But above 24GB, there should be enough in many cases. I have 32GB and that works fine for my needs (24 megapixel frames with the occasional larger panorama). If budget allows, 64GB is nice to have when working with higher megapixel images, or if you want to keep several large images open in both Lightroom Classic and Photoshop at the same time.

What are your settings in Preferences->performance when you select custom for the graphics processor? Is use GPU for export selected?

The limiting factor on your M1 mini is probably the 16 Gigs of memory. I recommend 32 GB for Apple silicon macs as the ideal amount that balances performance and price. 16 is just a bit too low but still reasonable with 8GB unworkable with high MP camera files. 

No clue if Apple will release a M4 mini soon. They are generally not so predictable and tend to 'forget' the mini line for a long time. It is true that the Pro and Max chips in any version are quite a bit faster than the base. The difference between single digit version upgrades are not so big. Less ig than the difference between Max and base.