samba - Jun 2003 - Samba slow performance when switch from USER=SHARE to USER=DOMAIN on WinXP clients

Dear List:

I have a network (about 30 PCs) that was working fine using USER=SHARE. 
Last weekend we switched over to take advantage of a Win2K server (recently 
added to the network) to be used as a PDC, Active Directory, etc. The 
network clients are a mix of WinXP, Win2K-SP3, and WinNT-SP5.

After the switch, the WinXP clients started experiencing a severe slowdown 
after a short period of time. The time before the symptoms occur varies 
from a couple of minutes to maybe an hour. If they reboot, the performance 
is again normal. The slowness symptoms are exhibited as random, major 
delays in opening a Word doc or Excel spreadsheet, navigating with 
Explorer, etc. The application will open at normal speed, the document 
loads, but then the hour glass cursor will stay present for up to 20 or 30 
seconds before control is returned to the user.

Misc Info:
Running Samba 2.2.8 on Sun Ultra 2 server with Solaris 7.
Running ftp to retrieve files from the server show performance above 9MB/sec
Copying files from the server to the WinXP PCs seems fine.
Running Samba at debug = 2 for that PC shows normal file opens / closes.
Running Samba at debug = 3 shows a lot of info, but none discernable as a 
problem (I'm not a SAMBA expert, but have been using for some 6 or 7 years 
now.)
Using local, not roaming profiles.
Win2K Server on a P3-450MHz PC - sole purpose is as a PDC and a license / 
software metering server

Settings were for USER=SHARE
[global]
	workgroup = SKEES
	log file = /var/opt/samba/log.%m
	max log size = 2000
	name resolve order = host wins bcast
	max open files = 1000
	socket options = IPTOS_LOWDELAY TCP_NODELAY
	os level = 255
	preferred master = Yes
	wins support = Yes
	kernel oplocks = No
	guest account = guest
	create mask = 0660
	directory mask = 0770
	force directory mode = 02000
	hosts allow = 192.168.254.
	hosts deny = 0.0.0.0/0
	short preserve case = No

Current Settings for USER=DOMAIN
[global]
	security = DOMAIN                                   <-----------------Added
	password server = *			<------------------Added
	workgroup = NTDOMAIN 		<--------------changed
	log file = /var/opt/samba/log.%m
	max log size = 2000
	name resolve order = host wins bcast
	max open files = 1000
	socket options = IPTOS_LOWDELAY TCP_NODELAY
	os level = 255
	preferred master = Yes
	wins support = Yes
	kernel oplocks = No
	guest account = guest
	create mask = 0660
	directory mask = 0770
	force directory mode = 02000
	hosts allow = 192.168.254.
	hosts deny = 0.0.0.0/0
	short preserve case = No
	encrypt passwords = yes		<----------------Added