Samba speed (too slow)

Hi all, A while ago (a few weeks) I installed a sambaserver on a Suse 8.1 box. I thought it was ready for "production" but I found a problem. I managed to get winbind autenticate the users, but the response of making a networkconnection with Win-clients is rather slow. Today I tried to copy a file of 162Mb on it and this took about tree quarters of an hour. Any suggestions to diagnose this problem ? B.T.W. the switch (=hub-like device) indicates the NIC runs at 100Mb. TIA -- Met vriendelijke groeten, Koenraad Lelong R&D Manager ACE electronics n.v.