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Fri, Dec 18, 2020 11:32 AM

Lightroom @ M1 Mac causes extreme writes to disk when full GPU acceleration is used.

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.).

This conversation has been merged. Please refer the main conversation:

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

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Adobe Administrator

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6 m ago

This thread is being merged into an authoritative thread for better tracking and response. 

Please don't make duplicate posts about the same issue.