Please be careful to only discuss one problem per bug report. If you're experiencing multiple problems then please open separate bugs for them.
Continuing with this bug...
I suspect the problem here is that disk IO is directly affecting animations. They shouldn't normally be related to each other, but one way that can happen is if gnome-shell is blocked in writing a log message. It can become blocked if there are regular log messages being written, and then every 5 seconds the kernel will block in order to flush to disk.
Please run this command in a Terminal window:
journalctl -f
Now reproduce the problem again and please tell us if the Terminal window shows NEW log messages while the freeze/stutter is happening.
Please be careful to only discuss one problem per bug report. If you're experiencing multiple problems then please open separate bugs for them.
Continuing with this bug...
I suspect the problem here is that disk IO is directly affecting animations. They shouldn't normally be related to each other, but one way that can happen is if gnome-shell is blocked in writing a log message. It can become blocked if there are regular log messages being written, and then every 5 seconds the kernel will block in order to flush to disk.
Please run this command in a Terminal window:
journalctl -f
Now reproduce the problem again and please tell us if the Terminal window shows NEW log messages while the freeze/stutter is happening.