codeigniter session expires frequently

[eluser]InsiteFX[/eluser]
The 2 lines with comments are what controls the session timings, but the session library updates with a new session_id every 5 minutes.

Code:

$config[‘sess_cookie_name’]      = ‘ci_session’;
$config[‘sess_expiration’]      = 7200;            // change this using seconds.
$config[‘sess_encrypt_cookie’]  = FALSE;
$config[‘sess_use_database’]    = TRUE;
$config[‘sess_table_name’]      = ‘edu_sessions’;
$config[‘sess_match_ip’]        = FALSE;
$config[‘sess_match_useragent’] = TRUE;
$config[‘sess_time_to_update’]  = 300;            // and this one

InsiteFX