Xtoolwait is a utility which starts an X client
in the background, waits for a window to be mapped
on the root window, and then exits. Xtoolwait can
improve performance for users who start a bunch of
X clients automatically (for example, xterm,
xlock, xconsole, ...) when the X session starts.

Install xtoolwait if you would like to try to speed
up the startup time for X sessions.