samba - Feb 2004 - samba read and write very slow

Our samba server is a linux redhat 7.2 SMP (2 PIII 600Mhz) pc with 1GB RAM and
only 260 Mo for swap,
SCSI disks, a 10/100 3com ethernet card, and samba version 2.2.7-3 : that should
be fast !!!
All our servers and computers are on only 1 switch that does 100Mb/s.
The samba server network card runs indeed at 100Mb/s (the "100" light
is on, the "10" light is off).

It takes only 14 seconds to upload a 90MB file using FTP from a windows XP
computer (let's call it
client1) to the samba server.
BUT, the same file is transfered in 8 minutes (!!!) (upload or download) using
SAMBA.

We tested the same transfer from another windows XP computer (let's call it
client2) : it takes the
same 8 minutes time.

We tested the same transfer from client2 to 2 other samba servers (a Redhat 8
with 1 proc and IDE
disks with samba 2.2.7-5 and a Redhat 9 with 1 proc and IDE disks with samba
2.2.7a-8) :
I takes only a few seconds !!!

We tried using the same smb.conf file on the slow samba server (redhat 7.2), but
it doesn't change
anything.

So, our question is :
what do we have to change on the slow samba server (redhat 7.2) ???
Do we have to install at least redhat 8 ? samba 2.2.7-5 ? anything else ?

Thanks for any help !!

Here is our /etc/smb.conf file (on the slow samba server) :

[global]

# workgroup = NT-Domain-Name or Workgroup-Name
  workgroup = WORKGROUP

# server string is the equivalent of the NT Description field
  server string = Kronos Samba Server

  load printers = no

  log file = /var/log/samba/log.%m

# Put a capping on the size of the log files (in Kb).
  max log size = 50

# Security mode. Most people will want user level security. See
# security_level.txt for details.
  security = user
# Use password server option only with security = server
;   password server = <NT-Server-Name>

# Password Level allows matching of _n_ characters of the password for
# all combinations of upper and lower case.
;  password level = 8
;  username level = 8

# You may wish to use password encryption. Please read
# ENCRYPTION.txt, Win95.txt and WinNT.txt in the Samba documentation.
# Do not enable this option unless you have read those documents
  encrypt passwords = yes
  smb passwd file = /etc/samba/smbpasswd

  socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192

  dns proxy = no

[homes]
  comment = Home Directories
  valid users = %S
  browseable = no
; this was "writable" (no "e") before :
  writeable = yes
  create mode = 0664
  directory mode = 0775