Codeigniter 3-slow loading

I used Codeigniter 2 version for quite a long time, I liked the speed of work.

I put the recently released version 3 on the open server. There was a feeling that the framework began to work longer...

I started to dig into what was wrong, it turned out that when connecting the database library class, the framework loads for a whole second longer when the default page is loaded...

Page rendered in 1.0395 seconds

Imho this is too much, has anyone encountered this? Or maybe this is a problem only on open server, and on the "normal" server will be normal? (I haven't checked it myself yet)

My Settings database.php:

$active_group = 'default';
$query_builder = TRUE;

$db['default'] = array(
	'dsn'	=> '',
	'hostname' => 'localhost',
	'username' => 'root',
	'password' => '',
	'database' => 'seocases',
	'dbdriver' => 'mysqli',
	'dbprefix' => '',
	'pconnect' => FALSE,
	'db_debug' => TRUE,
	'cache_on' => FALSE,
	'cachedir' => '',
	'char_set' => 'utf8',
	'dbcollat' => 'utf8_general_ci',
	'swap_pre' => '',
	'encrypt' => FALSE,
	'compress' => FALSE,
	'stricton' => FALSE,
	'failover' => array(),
	'save_queries' => TRUE
);