I've noticed that compilation time greatly depends
on a terminal you run it in, at least for one particular
project which prints lots of information during build
process. When I redirect it to a file it speeds the
compilation time by 30% and when it's run in a terminal
(konsole or gnome-terminal) top shows that X+terminal
consumes about 20% CPU load.
I decided to compare different terminals in terms of
scroll speed, and here is what I found :
rxvt : 1
xterm : 2.4
konsole : 6
gnome-terminal : 11
emacs : 42
Meaning that for instance rxvt is 42 times faster than emacs.
Well... actually I don't know what to add, these results look
pretty bad to me. It means that I will never compile in emacs
window and should abandon all terminals except for rxvt.