choosing mencoder????

[mustafa]

i use ubuntu 5.04
i am a new user to xvid and encoding in general as well.
i installed mencoder from apt-get.
there were a few option among the mencoders.

mencoder-586 - MPlayer's Movie Encoder
mencoder-custom - MPlayer's Movie Encoder
mencoder-k6 - MPlayer's Movie Encoder
mencoder-k7 - transitional dummy package which can be safely removed

i chose mencoder-k6 because the description says its for
amd athlons.
but i have a sempron.


should i install some other version or install mencoder-custom
because it says it for your computer.

i really need a performance boost because a have arounf 80 GB
worth of file to be encoded.