Joomla Website Very Slow Require FIX

Hi My website is running super slow sometimes and I have no clue what is going on. I am using bluehost Pro package. The support said it might be caused with cpu throttling issue. and send me a link. [login to view URL] My website are using joomla. I have install ACESEF on it, not sure is it because of this plugin. my major website on this account is [login to view URL] and [login to view URL] In short, I would like to have my website load within 4 sec or as quick as possbile. Thanks.