[Samba] Samba performance too low when writing to macosx

[Francisco J. León]

Machine A : macosx 10.3.5 , samba 3.02, powerbook 12" 1.0ghz 256mb ram
Machine B : slackware 10, samba 3.05, athlonxp 2100, 768mb ram

Using smbclient:

1) B does GET from A receiving speed is 6MB/s (about the top speed on 
my lan i can get)
2) A does GET from B receiving speed is 0.08MB/s
3) B does PUT to A receiving speed is 0.3MB/s

Why is speed so slow when writing to macosx? And why the difference 
between requesting data to be written on macosx and receiving data on 
macosx?

Is there anything i can do?