WordPress plugins and server resources
One of most popular reasons causes your WordPress slow is using too much plugins. This is pretty obvious, because plugins have functions those need server resources to handled. That also means, the less plugins you use, the shorter time your website need to load.
But, sometimes you found that your site's loading time is too long and you don't use too much plugins. So, what is the problem? The fact is some plugins need too many server resources to execute its scripts. And if you do't have enough powerful server, that will make your website slow.
OK. So, what are those plugins? What if we need to use them? Those are very common questions. I will list some of theme out here and you will have an idea what to use and what to avoid...
Plugins those slow down your website
Plugins those have functions to increase internal links, pageviews and reduce bounce rates is in the list. Because it will need a lot of ram & CPU to execute its scripts. You could turn it off depend on your need, but these are plugins that everyone need. But if you have over than 10000 posts, be careful with these plugins. It will spend you a huge cost of server resources.
Everytime it executes to find related posts, it has to do a lot of query on your database, then split output data to display the related posts on your site. Even when you have set random post display, each time you hit reload, it will load data once again.