LrC is using my slower GPU and making my macbook unusable.

[beacon_1257]

I'm new to Lightroom from Capture one. My macbook runs great on Final Cut Pro editing 4k60 videos and on Capture One but when it comes to LrC some features make it unusable. With graphics switching off on the mac, and all combinations of accelerator on in LrC, I would expect LrC tro use my more powerful graphics card. Ai Denoise takes 45 seconds or more and uses my fast card, landscape mask takes longer but uses my slow card and makes my computer freeze up until its finished maxing out my gpu at 96%. Anyone have a cure for this? I want to only use my fast card. I have a 2019 Macbook Pro 16", 2.4 GHz 8-Core Intel i9, 64 gb Ram, AMD Radeon Pro 5600m 8gb Graphics Card (fast) and UHD Graphics 630 Card (slow) . I'm running Sequoia. 

[johnrellis]

Some diagnostic steps:

1. Triple-check that Automatic Graphics Switching is indeed off:

https://support.apple.com/en-in/102265

2. Make sure computer is plugged in and not running on battery.

3. Restart the computer.

4. Do the LR menu command Help > System Info and copy/paste the entire contents here so we can see exactly which versions of hardware and software LR thinks you're running and important LR options that are set.

[beacon_1257]

I have triple checked and graphics switching is turned off. Plugged in. Restarted. I have tried all combinations within the Performance tab so what you see in the info I paste is the last combo I tried. In that tab it shows my AMD Radeon 5600m as the gpu used. 

Lightroom Classic version: 15.0.1 [ 202511041508-dddee541 ]
License: Creative Cloud
Language setting: en-US
Operating system: Mac OS 15
Version: 15.5.0 [24F74]
Application architecture: x64
Logical processor count: 16
Processor speed: 2.4GHz
SqLite Version: 3.36.0
Adobe GSDK Version: 1.4.0.171

Power Source: Plugged In, 100%
Built-in memory: 65,536.0 MB
Dedicated GPU memory used by Lightroom: 182.7MB / 8,176.0MB (2%)
Real memory available to Lightroom: 65,536.0 MB
Real memory used by Lightroom: 1,738.5 MB (2.6%)
Virtual memory used by Lightroom: 40,255.0 MB
Memory cache size: 26.1MB
Internal Camera Raw version: 18.0 [ 2389 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 510MB / 32767MB (1%)
Camera Raw real memory: 583MB / 65536MB (0%)

Cache1:
Final1- RAM:473.0MB, VRAM:0.0MB, DSC01524.ARW
NT- RAM:473.0MB, VRAM:0.0MB, Combined:473.0MB

Cache2:
m:26.1MB, n:410.0MB

U-main: 85.0MB

Standard Preview Size: 2880 pixels
Displays: 1) 3584x2240

Graphics Processor Info:
Metal: AMD Radeon Pro 5600M
Init State: GPU for Export supported by default
User Preference: GPU for Display disabled
Enable HDR in Library: OFF
GPU for Preview Generation: Off (S5_7)

Application folder: /Applications/Adobe Lightroom Classic
Library Path: /Users/beacon/Pictures/LightRoom Catalog/LightRoom Catalog.lrcat
Settings Folder: /Users/beacon/Library/Application Support/Adobe/Lightroom

Installed Plugins:
1) AdobeStock
2) Aperture/iPhoto Importer Plug-in
3) DxO PureRAW 5
4) DxO PureRAW 5 Importer
5) Flickr

Config.lua flags:

[johnrellis]

Back when Intel Macbooks were newer, I recall posts here about reports that GPU switching was fussy and not reliable. (I had a Macbook Pro 2019 but didn't observe that problem.)  In the last year or so, there have been a large number of reports here about problems with the AMD 500- and 5000-series GPUs. Apple had released a buggy driver in Mac OS 14 that LR tripped over, and it didn't get fixed until many months later in Mac OS 15. There are still scattered reports here of issues with the AMD GPUs.  Intel Macs are self-evidently not a priority for either Apple or AMD.

[beacon_1257]

Well I am debating on upgrading to Mac Os 16 if I knew that would fix the problem but man I hate to do that cause it may creat more. So you think this is a mac problem and not a lightroom problem? 

[johnrellis]

"I am debating on upgrading to Mac Os 16 if I knew that would fix the problem"

If I had to guess, updating to Mac OS 26 [sic] wouldn't solve the issue. I doubt Apple has made any changes to the Graphics Switching feature, which only applies to the old Intel dual/GPU Macs.  The feature isn't available on Apple Silicon Macs, since there's only one GPU (part of the Apple Silicon processor).

"So you think this is a mac problem and not a lightroom problem?"

Hard to say where formal blame lies, but if you forced me to put up money, I'd give slight odds to it being a Mac OS problem. LR does have code for particular GPUs -- it uses the generic graphics APIs presented by the operating system.

You could try updating to Mac OS 25 and then rolling back if it makes things worse. But Apple makes it quite tedious to roll back:

https://www.macworld.com/article/671318/how-to-downgrade-macos-revert-back.html

They really want to get people off old versions and keep them off.

[beacon_1257]

Well I figured out that 26 is extra demanding of the gpu to run liquid or whatever it's called so that is a no go. 

[beacon_1257 · Accepted solution]

Ok I think I got it figured out. So I did some command prompts to change which gpu is being used and that worked with LrC using the fast one but the problem came back after a restart and it used my slow one. Then I tried this: First I entered this into terminal sudo pmset -b gpuswitch 2. This sets "Switch between discrete and integrated graphics cards automatically while running on battery power"
Then I think I entered this sudo pmset -a gpuswitch 2. This sets " Automatically switch between discrete and integrated graphics card (this is your laptop's default setting)"
. And then I switched the graphics accelerator fully on within LrC Preferences, then a SMC Reset, and that combination seemed to do the trick. I tried so many different combinations so I can't remember if I did the the second command (sudo pmset -a gpuswitch 2) or not though but currently under system settings graphic switching is set to off but my computer is automatically switching both plugged in and not except for LrC which uses my fast gpu regardless. . Denoise AI still takes 45 seconds but Landscape Mask completes in about 3 to 4 seconds vs over a minute and now I can do other tasks at the same time, like watching a video. So stoked I don't need a new computer!!! This is where I got the prompts for whoever wants to try this if they have this issue. https://nathansnelgrove.com/2020/03/how-to-force-your-macbook-pro-to-use-its-discrete-graphics-card-...