Lightroom Classic & Desktop: disk read/write to SSD M1 Macs with Rosetta

Wow, somebody complaining that Lightroom is running too fast? It must be an April Fools joke.

My slow Intel Windows machine writes 50% faster than that and with years of using SSDs, none have failed yet. A really fast NVMe drive will write that much data in under 10 seconds.

So as the comedian said: whatca smokin Charlie? 

New updates,

It is probably swap, OS X gives too much mem to LR.

Disabling Graphics accelleration writes less to disk.

Not using external monitor writes less to disk.

Scrolling on develop seems to be when the disk usage is at peak.

I have created posts in 2 big OS X forums and people are looking into it too.
It's widespread.

Already asked them to post their findings here.

Honestly, I was at first very sceptical in regards to Carlos's reports but it is definitely a REAL ISSUE.
Swapping is all fine on modern machines but writing hundreds of gigabytes of data in a few hour session in Lightroom Classic is definitely not. Even the best SSDs (I mean, assuming real-world durability being as high as 1petabyte write lifetime) cannot survive this in the long run!

I have MBP 16GB/1TB so this behaviour is not limited to 8GB machines.

My last test was as follows:

- Launched nothing except Lightroom Classic.
- Lightroom Classic process sits at around 13-14GB of memory but inspecting the process shows that Virtual Memory grows steadily as you operate in "Develop" tab.

- What's most important this is reflected in writes to disk done by "kernel_task". In 15 minutes of scrolling through images and applying some presets at Random and I'm at whopping 20GB written to disk by kernel_task . And this is not some weird "cache writes" that do not affect the SSD like some people try to tell us.  SSD health tools confirm those writes.
- It doesn't happen when scrolling images in "Library" and basically doesn't persist when I do nothing or close Lightroom Classic.

I have no idea what's the reason but it seems like some Lightroom/Rosetta/Swapping bug. Feels almost like using Lightroom Classing @Rosetta makes kernel constantly drop GPU's memory content on disk (which would explain why disabling GPU acceleration helps a bit...).

Please Adobe, have a look at it!

The same thing happens with Lightroom CC. I think it's just basically massive memory leak by Adobe software. It'd be nice to verify against Intel machines.

Well, I guess it's the time to switch to Capture One (it does not do that, verified). 

ANOTHER UPDATE AFTER SOME INVESTIGATION:

Resetting preferences, rebuilding catalogue and all those tweaks did not help. 

What helps is playing with GPU acceleration settings.

For me, with the following setup:

- MBP M1 16GB RAM / 1TB

- No external display (I don't have access to mine at the moment and I'm afraid it's going to make an impact...)

The situation is following with different GPU acceleration settings:

- Full acceleration on:

  - Lightroom reserves around 23-25GB Virtual Memory at least;

  - ABSOLUTELY CRAZY SWAP WRITES

   ... and awesome performance.

- Basic acceleration:

   - Lightroom reserved around 16GB Virtual Memory;

   - OK behaviour, kernel_task is not writing to swap like crazy.

    ... performance still fine (as in very decent upgrade from 2016MBP13)

- No acceleration:

   - Lightroom reserved around 12GB Virtual Memory;

   - OK behaviour, kernel_task is not writing to swap like crazy.

    ... performance oh well, if that I'd have to live with, I'd be pissed because this is not what I've expected from this machine.

All in all, I think the reason for this madness with full GPU acceleration on is here:

When full acceleration is on Lightroom claims 10.5GB out of 16GB of unified RAM and writes some that to it like crazy. That results in crazy swapping. It's actually amazing how good it functions on M1 mac, no slowdowns but that heavy writes seem really dangerous. Even best SSDs cannot survive for more than 2-3 years 1-2TB writes per day. 

For now, I can live with basic acceleration and keeps fingers crossed that it'll solve the problem for me even with 4k display connected.

But it looks like something that Adobe SHOULD AND CAN SOLVE.

At the very least there should be an option to set memory value to let's say, 2-4GB.

It would still probably give us some performance improvement without crazy disk writes, at least on 16GB models. 

@Rikk 

What can we do speed things up here?
Is there any logs that I can provide to help you look into this?

When full GPU acceleration is turned on (it's a default) Lightroom (M1 native) causes an extreme high number of writes to disk coming from `kernel_task`.
By extreme, I mean: 15 minutes of scrolling through images and applying some random presents and I'm at a whopping 20+GB written to disk by kernel_task. This doesn't stop after some time, disk writes continue to grow all the time. SSD health tools confirm those writes, one can easily reach 1TB of written data just because of Lightroom running without actually saving anything to disk. Modern SSDs have good longevity but with extended usage, this kind of behaviour will surely kill even the best one. 

At least with M1 Mac with 16GB RAM that I have this dangerous behaviour stops when I disable full GPU acceleration and enable basic one. 

This seems like a bug coming from the fact that M1 Macs are quite happy to provide any memory space needed by swapping and the fact that Lightroom recognized GPU Memory available as 10.5GB (so 10.5GB out of 16GB of "real" memory!) and writes to those 10.5 GBs like crazy.

1. At the very least the default setting should be basic acceleration and turning full acceleration should be accompanied by a warning.

2. Lightroom shouldn't use 10.5 GB GPU memory. It most probably doesn't need that much to achieve decent performance gain.  Maybe it would be the best if Adobe would allow to set it manually. 
3. And well, the best would be if Adobe would manage to make GPU acceleration behave more orderly in general, but that's probably harder given my experience ;) It seems like it's a memory leak all in all.  Otherwise, why the difference between basic and full acceleration while I'm actually not doing any heavy image edits (brushes, masks etc.)?

Exactly same things are happening with Lightroom Classic (but it's not native so you can always blame this on Rosetta; not in this case.).

Update:

With basic acceleration on the same thing happens but only after prolonged time of Lightroom being opened. It can be completely unused, it's enough to leave it open. That makes it quite obvious that it's a memory leak. 

Commenting here to note that I've run into the same 'problem' on both the 8GB RAM version and the 16GB RAM version. 

Even did a head-to-head comparison against an intel MBP for the same workflow and noted that the RAM usage is significantly higher (and hence 'swap used' is also much higher).

I was the OP on this reddit thread (video included) 

https://www.reddit.com/r/Lightroom/comments/kg4bpm/investigating_lightroom_ram_performance_on_apples/

That being said, I'm open to the possibility that this isn't an "Adobe" problem but more of a result of the new M1 design. Still agnostic about it though, no technical background. 

New update:

Even with with GPU acceleration disabled I was getting around 100gb/hour of writes (down from around 200 lol) but I'v found that creating Smart Previews and disconnecting the disk reduces further the disk writes. I haven't tested extensively but it seems to be at around 25-35gb/ hour. 

To reduce the disk writes, I have disabled every program, quitting Adobe Cloud, dropbox, closing safari etc etc, there's only LR running because he takes up every single bit o ram available.

We urge you Adobe to fix this ASAP. It has been reported that the 16GB version has the same issue, so it's not directly related to the RAM shipped with the Mac M1's. 

Adobe pls fix this ASAP. This is a showstopper for most serious LR users. 
The swapping is out of control and it’s quite clear this is an Adobe issue since it also effects the native app. 

Following this thread for sure. I just got a MacBook Air 8c/8gpu/8GB/512GB and am coming from a MacBook Pro 15.4in/16GB/512GB/560x. The Air I was editing about 100 photos for the first time, and it got hotter than I was hoping (basing my performance hopes on all those YouTube reviews, especially that Air was up to the task and enough). I even wanna say it got as hot as my ‘19 Pro used to.

What seems to be a sure positive between the two, is I feel the Air definitely has better battery life than the Pro I used to have.

I will definitely see what numbers I get in my next editing session regarding the swap/kernel. I’m glad to see it’s not just me, but I’m also sad to see it’s not fixed yet.

Also, I’ve got 14 days to return, and I’m not sure if I should hold out on solution, or be return and get a 16GB Air, or even a Pro for the fans, BUT be laptopless for almost a month because only way to get 16 is through Apple right now.

Same problem here. 

I purchased an Mac mini M1 with 16GB/256GB for a better performance experience than on my old windows machine. First tests with LrC were awesome, but than I looked into the swap usage... After editing around 20 RAW images over 100 GB of data were written to the SSD. That is crazy. 

The problem occurs with Lr CC too, so it is an adobe problem, not an apple one with rosetta. 

I am afraid of using LrC because my 256GB SSD should have even a lower TBW life time as the higher models.

It seems switching the GPU acceleration to Basic Mode fixes the problem, but the performance of LrC is a piece of sh*t on a 4K display after that. 

I really regret purchasing two more years of creative cloud some month ago. 

Any updates to this issue?

I’m adding to the voices here as someone who’s seen this issue on their new 16 GB M1 MacBook Pro.

I’m frankly afraid to use Lightroom right now because I’m quite certain that the ridiculous swap usage will significantly reduce the performance off the machine within a year or two. I have experienced it firsthand with my previous Mac.

Adobe team, please look into this and fix this issue. This is probably a severely under reported one, as the swap memory of these machines is fast enough at the moment for the issue to be unnoticeable. People have no idea it’s killing their machines like nothing else, and they will see it a year or two down the line when it’s too late to regain the last performance. 

As a person who loves using Lightroom, I thought I’d bring Adobe’s attention to this issue in the hopes that it is fixed and I can continue using it.

I suspect this is a difficult and fundamental design problem with LR classic, and not easy to fix. Thus the lack of response from anyone at Adobe. Given that hardly anyone is complaining since it’s hard to notice the issue, they’re just ignoring this. 

Adobe, we deserve an answer. We are paying customers. This is not an open source project. At least let us know that you can replicate the issue and that you’re working on it. Thank you.