OpenSUSE Network :: Transfer Speed Between Samba Server And Win Clients

I have the problems with transfer speed between samba and Windows XP clients.

Samba server configuration:
Quad Core 6600 CPU.
4 Gb RAM
OpenSUSE 11.2 with kernel "2.6.31.12-0.1-desktop"
Samba - samba-3.5.1-1.1.i586
Test: 4 GB File copying. One file.

Transfer speed from Samba Server to Windows 7 and XP clients:
(Windows clients copy file from Server share -> to local drive)
From Server to Windows 7 client 1:
85-90 Mb/sec
From Server to Windows 7 client 2:
90-100 Mb/sec
From Server to XP1 client 3
75-100 Mb/sec

Transfer speed from Windows 7 and XP clients TO Samba Server:
(client copy file from local drive -> to server Share)
From Server to Windows 7 client 1:
12-20 Mb/sec
From Server to Windows 7 client 2:
30-35 Mb/sec
From Server to Windows XP client 1
20-27 Mb/sec

(Copying file from Windows local drive to Windows remote share)
From Window 7 client 1 TO Windows XP client 1
40-50 Mb/sec
From Window 7 client 2 TO Windows XP client 1
50-60 Mb/sec

Copying file from Windows 7 client 2 share -> TO Windows XP client 1 show me 100-120 Mb/sec speed permanent.
Copying file from Linux hosts to NFS server is stable 50-90
Mb/sec bidirectional.

This part of my smb.conf file
Code:
# version at /usr/share/doc/packages/samba/examples/smb.conf.SUSE if the
# samba-doc package is installed.
# Date: 2009-10-27
[global]
log level = 1
debug level = 0
max log size = 50 .....

I have very slow write speed when copying file from Windows clients to Samba Share. Samba speed is slower than Windows native clients connections ?