Performance on Mac: fast interface but slow rendering!

(I use an MacBook Pro M1 Pro 32GB, which I’ve been happy with for my Lightroom Classic usage.)

An M2 MacBook Air is a good Mac for light Lightroom Classic usage, but not ideal for heavy usage, for the reasons below.

Export rendering:

How much Unified Memory does the M2 Air have? The reason for that question is that export rendering is GPU accelerated, but full GPU acceleration can happen only if the GPU isn’t starved of memory, and it gets that memory from RAM, which is why Apple calls it Unified Memory: It’s shared among macOS, applications, and graphics hardware. For a MacBook Air, I would expect 8GB Unified Memory to result in slow export, 16GB to be sort of OK, and 24GB to be the best you can do because that’s as far as you can go with an Air. In the Lightroom Classic system requirements, 16GB is the minimum that Adobe recommends for full graphics acceleration, but being the minimum, memory crunches can still happen there, so I always recommend more than 16GB if the budget allows.

If full graphics acceleration is not available, export will fall back to the CPU, which will be slower and potentially hotter, and if that leads to thermal throttling (because there is no fan on the Air), then it will be even slower.

Preview rendering:

This works completely differently than export. Previews are currently all done on the CPU; the GPU is not used at this time. The more CPU cores there are, the faster it can get through previews because it is able to distribute them among cores in parallel (if that option is enabled). There are two problems the MacBook Air has here: It has the fewest CPU cores (8) of any Apple Silicon Mac, and it has no fan. So it is able to render the fewest previews per clock cycle, and if extended preview rendering causes the CPU to get hot, it has to slow down to cool off because there is no fan.

You might want to watch some of the comparison videos on the ArtIsRight channel on YouTube. He regularly tests Mac models as they come out, and Lightroom Classic is one of his tests. His charts can help you decide what kind of Mac you’ll need to reach a certain level of performance. He does make a point of saying the non-Air Macs get a lot of help from the cooling fans, because when the CPU/GPU is kept cool it doesn’t have to slow down during long renders.

Here is his chart comparing export times for 1000 images on various Mac configurations:

(I added the orange “M2 Air” label so you can find your computer)

Here is his chart comparing 1:1 preview rendering times for 1000 images on various Mac configurations:

If you want to see the whole video, here it is. You have an M2 and it says M3, but I picked it because it is more recent so you can compare your M2 Air against more recent Macs:

And one more thing regardless of Mac, make sure the internal SSD is not anywhere close to full. An SSD with no free space will slow down the fastest hardware.

Please post your System Information as Lightroom Classic (LrC) reports it. In LrC click on Help, then System Info, then Copy. Paste that information into a reply. Please present all information from first line down to and including Plug-in Info. Info after Plug-in info can be cut out as that is just so much dead space to us non-Techs and it takes up vast amounts of scroll space making the reply less readable and less likely that others will bother with your post.

The MacBook Air has no active cooling (i.e. no fan). Therefore, with tasks such as exporting, buildng previews, the CPU and GPU (export only) will back off took reduce their temperture. You didn't mention how much memory you have on the MB Air how many images you're exporting, which would would have provided a useful indication. 16GB will do much better than 8GB with LrC.

As for exporting, I've just used my M3 MacBook Air 16GB to export 130 Canon EOS R6 Mk2 images as full res/size in 2 minutes. That's not bad considering the CPU/GPU temperture could only be controlled by reducing clock frequency. Had I been exporting 1000 files, then I'd have split the export into smaller batches.

If Lightroom Classic does not have Full Disk Access, performance can be affected. Both you and bajanstefan18 should try this:

At this point Adobe needs to re-engineer LrC for the mac. Look at my laptop specs, you wouldn't believe the lengths I've gone to to make this applicaiton more responsive. Trimmed my catalog to 10% of the original size, everything is and has always been stored on my SSD, dropped my screen resolution, tried every version of the GPU accelration settgsin (what a joke), I've gotten rid of all 1:1 previes and replaced them with low quality 1280 previews. The stirking thing is if you edit in ACR, it's blistering fast, yes I understand it's not driving or pulling from a catalogue but it's been a disappointing few years with scare glimpses of acceptable functionality. Public or beta release, clear preview cache, maxed out cache, whatever you try all produces the same results with this application in particular. They need a beta of this application because as it stands, the public release stream doesn't invoke any degree of hope in anything but neglible improvement.