Joomla and Wordpress Websites Speed Issue

Hi My websites is running 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] also, some of my major websites that are requiring fix. [login to view URL] , [login to view URL], [login to view URL] , [login to view URL] they are all hosted in the same hosting account under bluehost. bluehost said probably because of one website script/plugin created such cpu throttling problem. 3 website are using joomla. I have install ACESEF on it, not sure is it because of this plugin. 1 website using wordpress. my major website on this account is [login to view URL], [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. The Requirement is : The websites above should be able to load fast (at most 4 sec) under MULTIPLE TABS visiting my site at the same time. Please understand my issue before bid on it. Issue = try use any browser and open 12+ tabs of [login to view URL] (or any of my websites above), you should notice a significant lag (10-20s) before each website start loading . I mean that for other normal webpages, if open 12 tabs, they should open at least one by one IMMEDIATELY. However, for mine, the first 2-3 tabs load quick, but you will notice they DO NOT open one by one immediately and have a significant LAG. Thanks. Re-posting this post.