Fastest Thread-Safe XML Read

Looking for any input on the fastest and most thread-safe way to read
some small (~8k) XML files from a local disk.

System.Xml.XmlTextReader xReader =
new XmlTextReader( new System.IO.StringReader( configFile ) );
lock( xReader )

Looking for any input on the fastest and most thread-safe way to read
some small (~8k) XML files from a local disk.

System.Xml.XmlTextReader xReader =
new XmlTextReader( new System.IO.StringReader( configFile ) );
lock( xReader )
{
while ( xReader.Read() )
{
if ( xReader.Name == configKey )
{
string tmpString = xReader.GetAttribute( "user" );
}
}
}

I don't want any try-finally stuff, just thread-safe reading, it's OK
to block for a moment as long as other readers don't hit any
exceptions or errors.

Thanks.