bitcomet & azureus setting problems

[XXXXXX]

i've tried to use bitcomet & azureus to download a same file (not at the same time), but the download speed of bitcomet is very slow.

azureus - 300k+,
bitcomet - 30k+ only.

is it setting problem or azureus is faster than bitcomet?
if it is just setting problem, what is the correct setting?
azureus is good but use too many memory...