How to speed up manipulating indexed files or folders on NAS?

Recently, I put big size files(like movies) with other achieved files to my NAS, I indexed them all into DT3. But I found when I rename folders or delete some of files, very slow to do that compared to directly manipulate on finder.

Connected between NAS and laptop with 1g cable. How can I speed it up?

Is the database also located on the NAS? How many items did the renamed folder contain?