Interesting circumstance. My computer's been slowing down terribly - disk and CPU temps going through the stratosphere. Yet the drive tests out OK.
After doing much digging, I found a file - 'adobegcclient' - in my Activity Monitor, that starts reading disk space like crazy. Opening Photoshop and Lightroom starts it off, and it never stops, even after you've quit. Gigabytes of disk activity while you're trying to work. It brings my machine to its knees.
Adobe has no fixes that I can find online yet. I don't think people are even aware that the system is doing this - they just think of CC as being slow.
I'm leaving Activity Monitor open, and checking to see when I start hearing my drive go apeshit. Quit the process, and I'm back to full function.
Anyone see a reasonable fix, let me know.