Speed Up logins
Turn on the 'Fast Logon Optimization' group policy setting. This allows someone to logon with cached credentials and get a desktop while background events are still occurring.
This feature is enabled by default, but you can disable it by using the following policy: Administrative Templates\System\Logon\Always wait for the network at computer startup and logon.
Two registry keys can be set for improved logon performance.
1: Turn on opportunistic locking on the XP clients
Review http://support.microsoft.com/kb/319440 and set the registry value BufferPolicyReads to 1 on all XP clients.
Note: BufferPolicyReads doesn't exist in Windows 7 (probably not in Vista either) - most likely because the code it was part of has been rewritten completely and the key isn't neccessary anymore.
Note File Reads will only be buffered when the the
BufferPolicyReads registry entry is created and is set to 1.
2. Review http://support.microsoft.com/kb/834350 and set the registry value InfoCacheLevel to 10 (hex) on all XP clients
Note: InfoCacheLevel also exists in Windows 7 but it defaults to 0x10 (caching for all files) unless specifically set to 0 (Disabled) or 1 (cache only 8.3 names). I.e. no action needed to turn it on in Windows 7 or Windows 2008 R2 - it's on by default there.