2 more users are logged in, most likely system used by drivers like mentioned, check Users tab.
https://social.technet.microsoft.co...wm3dwm1-in-task-manager?forum=w8itprosecurity
I don't have logonui.exe, but i'm pretty sure it's just there to initialize user session. That should go away a short moment after you log in.
My csrss.exe is only 2 and my dwm is just one. Maybe it's just that some graphics drivers require more than 1 dwm.exe running.
View attachment 55507