Seriously? I think this is more confirming that the person you replied to is right. Unless there is some reason that I can think of that only using 2 cores is a good thing?
Everything else—the rendering, scaling, compositing, etc.—runs on the GPU, not the CPU, where it uses hundreds of cores. Y’know, like a 3D game.
And, like a 3D game, it’s still slow, because it’s doing something genuinely hard and your powerful GPU still isn’t powerful enough.
A cursory search brought up this link, but you should read up on threads and the difference between CPUs and GPUs:
https://macperformanceguide.com/blog/2017/20171223_2311-why-...
Multiple cores are really good at handling a lot of smaller processes. Photoshop just has a couple really heavy individual processes.
Demo was 12,000 x 12,000 pixels, 2 orders of magnitude would be pictures of 120 x 120 pixels.
We did more with Photoshop in the past than 128px icons.
120 x 120 = 1.44 * 10^4 pixels.
4 orders of magnitude. And in addition to that, the RAW sensor information from the camera has given each pixel more 'depth'. Often times, each color is 12bit (36bit per pixel). There's more to each pixel than what's displayed on the screen: its not just a JPG you're viewing.