MacBook Pro M4 Max

[cgingrasquebec]

When the M4 Max processor came out, I read in a few places that LRC did not take advantage of all the power the M4 Max had, especially when exporting.

I've read the Release Notes for the December update (14.1) and they don't say anything about that. Can someone confirm that this was fixed?

[Conrad_C]

The statement is partially true, but needs context.

When it comes to taking advantage of the hardware, Lightroom Classic is not the best and also not the worst. I think I have seen ArtIsRight make the claim that Lightroom Classic is not fully optimized for the hardware, and I think what contributed to that view is his test result that Lightroom (cloud) seems to export the same test files faster than the older Lightroom Classic. 

If you look at ArtIsRight’s video below, he compared export times for Lightroom, Lightroom Classic, and Capture One when exporting 1000 61 megapixel raw files. His results were:

Lightroom 15:12 (min:sec)
Lightroom Classic 22:20
Capture One 45:21

So on an M4, Lightroom Classic is a fair bit slower than Lightroom, but for the same test, Lightroom Classic is over twice as fast as Capture One.

One reason Lightroom Classic is not the worst is that it can take advantage of GPU acceleration for export. Some of the competing non-Adobe applications do not, and they take longer to export.

When talking about whether an application takes advantage of “all the power” of the hardware, you have to be careful because hardware has many components (CPU, GPU, NPU, storage…) which are optimized more or less well depending on the feature. Different applications might be better optimized for some features and worse in others. It might not be possibile to find one application that always take full advantage of the hardware in all areas over all other applications. Even within Lightroom Classic alone, the Develop module, preview generation, export, and other tasks use a different balance of those components.

So Lightroom Classic could do a better job, but it certainly is far from the worst in export speed.

[cgingrasquebec]

Thank you for your answer. But my question was specifically for the Max version of the M4 processor, not for the M4 family as a whole. 

[Conrad_C]

The only difference the Max makes is that it has a few more CPU cores and a lot more GPU cores.

For tasks that are primarily CPU based, the M4 Max will be slightly faster than an M4 base or Pro because it has a few more CPU cores. Or, no faster if a process is single-core (because single-core performance is about the same across the entire generation).

For tasks that are primarily GPU based, the M4 Max can be potentially much faster than an M4 base or Pro. But this may not scale in a linear way; check Art’s export performance results for the M4 Max vs other M4 levels in the video where he compares them (see below).

Other than that, how well Lightroom Classic takes advantage of those resources is probably proportional to how well we already established it performs relative to other applications for the M4 in general. For example, because previews are currently CPU-based, the Max won’t speed those up much because there aren’t many more CPU cores. But anything using GPU acceleration may be noticeably faster on the Max due to having up to double the GPU cores.  As we already established, Lightroom Classic is neither the best nor the worst at fully taking advantage of those resources, but overall it does well enough compared to other applications. The last time I checked macOS Activity Monitor during a Lightroom Classic export, it did make heavy use of both multiple CPU cores and GPU acceleration to bulk export images in parallel (a lot faster than Photoshop would, for example).

One thing I’ll say is that “full use” of the Max probably only makes a difference for intensive bulk processing/exporting; you might not notice much difference between the Max and other levels if you’re processing just one or a few images.

Regarding whether it’s possible to confirm how “fully” it uses each component, Adobe release notes rarely go into that much detail. The release notes did cover when Lightroom Classic added GPU acceleration to export. The lack of detail may be that it’s difficult to promise a single number that will be consistent across configurations and use cases.