Execution speed depends on quite a few things, among them: Type of compiler (and which
optimizations switched on, and how good these are), quality of used algorithms and their
implementation, type of os, that is mainly: speed and behaviour of the task scheduler, number
of processes running (because your process will get only a fraction of available cpu time - the more
processes, the less time you get, the longer your task takes). So saying "de/encoding a dvd under
(some) Linux takes x times the same job under windows" is like comparing peas and apples.
There is, however, something which you can do under Linux which you can't do (easily) under
windows and which, of course, proves linux' (and most other *NIX brand) superiority :-)
That is, change the processes' priorities (how much cpu time they will get).
1. Login as root
2. Be sure not to have any application with important data open :-)
3. Encode something and measure the time (at the console:
time xvid <whatever input> will measure the time for you)
4. Now open up a (new) console, start the same encoding job again. At the console,
type ps x and search for your process, probably xvid or something like /usr/bin/xvid. Get the
number to the far left (the processes' pid) and type renice -19 <pid>. If it returns with a
line like 0
ld priority, new priority -19, then your process has the highest priority it can
have and should be finished faster.