CiviCRM running very slow on local network
And once again I had found out the answer on my own, took a lot of time though...  it is in components and administrator's civicrm.setting.php (both php file!)
just simply change both localhost (see the photos below) into your server IP
Simple as that (yeah I'm so noob TwT), I wish this can help those who have the same problem like mine, apology for my bad grammar english and stuffs :P