I regret upgrading to Photoshit CC 2015. It has several bugs damaging to my workflow.
1) Moving a selection does not work. Or rather, it works with a 5-10 second delay, but it mangles the selection and the delay means no feedback and thus it’s impossible to use.
2) Grab handles from the crop tool are the grab handles from hell: they won’t go away even after a tool change, hitting the escape key, etc. Moreover, at times, a screen shot will capture the (invisible) stuff behind the Photoshop window!
3) Scaling to Fit to Window to results in a blurry rendition (this also is in CC 2014).
4) Various unstable behaviors (crashes).
5) Bizarre and unpredictable slowdowns.
I have the dual D700 GPUs in my 2013 Mac Pro with 8-core 3.3 GHz CPU and 64GB memory and 1TB SSSD. It doesn’t get any faster.
These are GPU-related bugs. Turn off the GPU to fix. I’ve long advised disabling GPU support because of bugs, but Adobe has been removing the optimized non-GPU code, so many functions are now turtle slow with the GPU off. We’re screwed: the old fast code is gone, the new code is buggy GPU-based code. Some of this may be Apple’s fault (buggy drivers that were problematic from the start), and some may be Adobe bugs. I don’t know. But the end result is the same: a disaster for work.
I’m going to have to reinstall Photoshop CC 2014.