You could try adding some logging.
Add the following snippets to your web.config or app.config file.
...
<configSections>
<section name="log4net"
type="log4net.Config.Log4NetConfigurationSectionHandler,log4net"/>
</configSections>
...
<log4net>
<appender name="RollingFile"
type="log4net.Appender.RollingFileAppender">
<file value="c:\\log\myApp.log"/>
<appendToFile value="true"/>
<datePattern value="yyyyMMdd"/>
<rollingStyle value="Date"/>
<filter type="log4net.Filter.LevelRangeFilter">
<acceptOnMatch value="true"/>
<levelMin value="DEBUG"/>
<levelMax value="FATAL"/>
</filter>
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%-5p %d %5rms %-22.22c{1} %-18.18M - %m
%n"/>
</layout>
</appender>
<root>
<level value="INFO"/>
<appender-ref ref="RollingFile"/>
</root>
<logger name="NHibernate">
<level value="DEBUG"/>
</logger>
</log4net>
and then call the following line when your application starts:
log4net.Config.XmlConfigurator.Configure();
This will write a detailed log to c:\log\myApp.log
If it's NHibernate that's taking the time, you'll see what it's doing.
If there's a gap in log then the bottleneck is in the database.
To turn down the log verbosity for NHibernate level change this :
<logger name="NHibernate">
<level value="WARN"/>
</logger>
Brendan.