bandwith problems with freebsd 6.0

[LeifEriccson]

hello again

some days ago i mentioned that there are some bandwith problems with 
iperf and a freebsd 6.0 ( running on an wrap systems by pc-engines.ch 
with an amd geode cpu). meanwhile i did the same test with a linux 
system kernel 2.6.14 and i got a bandwith up to 52 MBit/s. does anyone 
of you know why i cannot get the same or even a better bandwith with 
freebsd? actually i want to keep the freebsd, because right know it uses 
just 17 MB of disk space compared to the linux with ca. 190 MB.

tnx dominik