Dolphin/Desktop slowdown during smb file transfer

Hi,

if I transfer a larger number of files from a smb share to the local harddisk using Dolphin, the filebrowser (not just the source/dest tabs, all of them) and also the desktop become quite sluggish. Is that normal and if not, what logs do you need and what steps can I take to fix the issue.

It began roughly in the last two months, it was fine before, the hardware has not changed, I am on latest stable.