samba - Jun 2005 - Problems sending transferling large files from windows 2000 to Linux, via gigabit ethernet.

Hi All,
 
I am currently using Samba v3.0.14a and it's incredibly responsive...except
when it comes to large files.
Currently my specs are as follows:

Santiago
Dell PowerEdge SC1420, which is using SATA (RAID 5), and reiserfs 3.6

Ottawa:
Desktop PC
Windows XP
100/10 Ethernet Card.

Douglas:
Desktop PC
Windows XP
Gigabit Ethernet Card.

These are the tests that I have performed: 

Test Set 1:
------------
1. Windows Copy from Ottawa to Santiago. (>1 GB)
	- Works but extremely slow...copy times vary wildly from 3 minutes to 30
minutes, but copy completes.
2. Windows Copy from Ottawa to Santiago. (<1 GB)
	- Works wonderfully.
3. FTP Copy from Ottawa to Santiago.
	- Works perfectly. 
4. SCP Copy from Ottawa
	- Works perfectly.

Test Set 2:
--------------
1. Windows Copy from Douglas to Santiago. (>1 GB)
	-Fails after 1 GB mark, approx 20 seconds in:
2. Windows Copy from Douglas to Santiago. (<1 GB)
	- Works wonderfully.
3. FTP Copy from Douglas to Santiago.
	-Works Perfectly
4. SCP Copy from Douglas to Santiago.
	-Works Perfectly.

---------------------
Here is my Smb.conf file.

socket options = TCP_NODELAY SO_RCVBUF=65535 SO_SNDBUF=65535 SO_KEEPALIVE
IPTOS_LOWDELAY read size=65535 max xmit=65535
hosts allow = 10. 127.
max log size = 0
security = server
password server = SRV01
password level = 8
username level = 8
username map = /usr/local/samba/private/smbusers
wins server = 10.0.0.212

[data]
   path = /data/SMB_Store/
   comment = CVS/Datashare
   browseable = yes
   writeable = yes
   create mode = 0777
   directory mode = 0777
   public = yes
   guest ok = yes
   read only = no


Has anyone come across this before ? 
Thanks very much for all for your help, 
Alex