MODx is being slow

Just after the installation of modx revolution 2.0.0 when you are using a proxy, you can’t access the manager interface to edit the System Settings.
In that case, you must execute the following request on the database directly :
update `cms_system_settings` set `value`=’’ where `key` in (’feed_modx_security’,’feed_modx_news’

Make sure your php.ini file contain values
memory_limit = 128M
max_execution_time = 120