Heres Why...
my first post HI ALL
ok the reason it does is several reasons
1.NOTHING but the games are runing on your gamecube
2.games are optimized to MATCH the system specs of a gamecube
3.Developers OPTIMIZE games for consoles
PLUS it floats from 32bit/64bit so they are optimized for the bittage so it only needs to operate at say 3/4-1/2 the processor speed
***NOTE: 2 and 3 are similiar but they are not the same AND 3 is only WHAT I heard from someone else***
i HOPE this answers your question