Most websites are built on CMS like Wordpress or Joomla. In other words, plain HTML website with few CSS will load instantly, but websites with custom theme and tons of PHP plugins, external content like chat, stats and cookies may bog down entire server. If your website doesn't load fast enough, please try the following:
1. Analyze page speed via Google: https://pagespeed.web.dev/ - it will give you insights and also solutions how to improve page speed. You should reach at least 50 in performance score. Site within 70-90 score is GOOD.
Note: PageSpeed Analitics or Insights by Google may take up to 20 minutes to process, it depends in theme, plugins, external content like chat and CSS. It will take some time for sure. Please be patient.
2. Login to cPanel then navigate "Resources". If you see "your website has been limited…" - that means CPU or memory limit has reached. You can either improve site load by removing unused plugins, external code (facebook/meta, twitter feeds etc.), replace theme or contact technical support in order to boost resources.
You should optimize website before requesting resource BOOST. Outdated PHP scripts, themes or plugins will continue to overload entire server, regardless of limits. If you done site optimizations, you may request resource boost via 24/7/365 Help Center. It's free of charge and permanent.