The prefix key C-x 5 is analogous to C-x 4. Whereas each C-x 4 command pops up a buffer in a different window in the selected frame (see Pop Up Window), the C-x 5 commands use a different frame. If an existing visible or iconified (“minimized”) frame already displays the requested buffer, that frame is raised and deiconified (“un-minimized”); otherwise, a new frame is created on the current display terminal.
The various C-x 5 commands differ in how they find or create the buffer to select:
Create a new frame (
Select buffer bufname in another frame. This runs
Visit file filename and select its buffer in another frame. This
find-file-other-frame. See Visiting.
Select a Dired buffer for directory directory in another frame.
dired-other-frame. See Dired.
Start composing a mail message in another frame. This runs
mail-other-frame. It is the other-frame variant of C-x m.
See Sending Mail.
Find a tag in the current tag table in another frame. This runs
find-tag-other-frame, the multiple-frame variant of M-..
Visit file filename read-only, and select its buffer in another
frame. This runs
You can control the appearance and behavior of the newly-created frames by specifying frame parameters. See Frame Parameters.