Does the GPU acceleration help the pano merge tasks?
What I observe is that on my iMac, pano merge of 50-70 MB NEF files can take 30 minutes and during most of this time, it's only using about 20% of the CPU. Then in the last few minutes, the LRC process pegs the CPU over 200%.
So the CPU usage for pano merges seem very uneven and seems to suggest that pano merge woudl benefit more from CPU than GPU performance.
And since some of the pano files I get are apporaching 1 GB in size, maybe IO is more improtant than GPU perofrmance as well?
In any event, Apple just announced new MacBook Pros and they are differentiating the various M1 Pro and M1 Max chips on the amount of unified RAM and the amount of GPU cores, with the more expensive M1 Max configurations having up to 32 GPU cores.
So for pano merge tasks, does having 32 GPU cores help over the base 16 GPU cores? Well you get more unified RAM in the chips with 32 GPU cores so it's not easy to separate.
"When configured (Preferences > Performance), Lightroom Classic can use a compatible graphics processor (also called a graphics card, video card, or GPU) to speed up tasks of displaying and adjusting images in the Develop module, the Library module's Grid view, Loupe view, and Filmstrip. Enhance Details is also accelerated by the GPU."
When I merged 9 Sony raws (about 20 MB each), Activity Montor showed the GPU was hardly used:
I'm not aware of the GPU having any particularly benificial role in merging panos.
On various tests, I've found that the time to merge panos is to all intents identical whether GPU is enabled or disabled. My tests have been carried out on: Late 2013 10-core Mac Pro with 64GB ram and AMD D300 GPU with 2GB VRAM, 16-inch MacBook Pro with 16GB ram and AMD with 4GB VRAM, and M1 Mac mini (1TB SSD) with 16GB ram. The M1 Mac mini is slightly faster than the Mac Pro and noteably faster than the MacBook Pro. A recent example being a Canon 5D MkIV 10 image pano took approx 23 seconds on the Mac Pro, approx 20 seconds on the M1 Mac mini, and approx 34 seconds on MacBook Pro.