Some accounts on shared computer are very slow

There are three accounts on a Mac mini: Mine, and two others.

My account runs well. It is fast enough. However, it takes ages to load.

If my account is left open, the other two accounts run extremely slowly. In order for them to run at all acceptably, I have to log off my account. Then they run fine.

This happens even if I have quit every application on my account.

(Once my account is loaded, it always runs fine, whether or not there are any other accounts logged on.)

Does anybody have any idea how I can fix this? Might it be something to do with Google Drive? That always seems to be the last thing to load.