Extreme System slowdown during saving file

[Corniger]

Hello,

I'm currently experiencing the following situation:

I'm editing images from an external M2 SSD drive, connected via USB 3.0.

I've created an action that automatically creates items, saves the file, deletes items and saves the same file in that version in a different folder on the same drive.

Everything is running super smooth for a while, then suddenly the saving process slows down tremendously (~30 minutes instead of a few seconds), the entire system comes to a crawl, but with 5% CPU usage, around 30% RAM usage and barely any disk usage. The mouse barely moves, enormous lag.

I also can't cancel the saving operation most of the time, though the last this started happening, I was able to click the cancel button, whereas normally it's greyed out. On the second attempt, without reloading anything, it saved just fine.

Once I shut PS down, the system is snappy as ever. Once I rebooted with PS "saving" and ater found, it had save both versions, but apparently "visually wasn't there yet".

Specs: Win 10, 2x Xeon e5-2667 v4, 112 GB RAM, Quadro M5000, txt attached.

[Kevin Stohlmeyer]

What happens if you save locally?

[frazzlesnap]

The available cache in the drive will eventually saturate, resulting in much slower operation until it refreshes. Some flash devices have very slow/very little cache, and will throttle quickly, like most cheaper usb drives. A good NVME drive shouldn't have much problem. My USB 3.2 adapter hooked up to a 2TB Seagate FireCuda 530 doesn't throttle much under any conditions that I can detect, so that might not be the issue for you.

[D Fosse]

The official advice from Adobe is to never save directly to an external drive. In addition to slow saving, the risk of corruption is very high.

Save locally, then move the file over.

[Corniger]

Thanks to everybody, I'll save locally on the next job.
Maybe it was the SSD cache (Sandisk Extreme Pro 2 TB, should have 26 GB) - though not only the saving, but also the entire system got slowed down massively. There's also 300+ GB free space left.
After the file was saved, the system still was that slow - until I closed PS. That's why I wasn't suspecting the drive. I never had this issue before, though I - apparently stupidly - have done this since at least a year without issues.