[split] ajax killing sessions?

Thanks for your response.  I am using the database driver and I am using MySQL -> MySQLi  

I think you might be right about ajax.  Here are my settings.  I am thinking about trying memecache or redis (I am running on AWS) so those options are pretty easy to get.  Any thoughts?

$config['sess_driver'] = 'database';
$config['sess_cookie_name'] = 'ci_session';
$config['sess_expiration'] = 7200;
$config['sess_save_path'] ='ci_sessions';
$config['sess_match_ip'] = FALSE;
$config['sess_time_to_update'] = 300;
$config['sess_regenerate_destroy'] = false;
$config['sess_expire_on_close'] = FALSE;

Thanks in advance!