In an August 2013 video, Cutts explains that page load speed is a ranking factor (Matt Cutts is the head of Google’s Webspam team).

It’s quite possible that your website is slow because of one of the five issues below. Check them out, and see how they relate to your site.

  1. Page Size — The bigger your page, the longer it takes to download, especially over slower connections.
  2. Time to First Byte — An increased time to 1st byte means there are too many SQL queries or non optimized SQL queries. This can also include server-side calls to third-party API. If you’re running WordPress, get the WordPress Plugin P3 Profiler to discover what plugins are running what queries and how long each one takes.
  3. Total Objects and Third-Party Objects — Too many objects on your page will require visitors’ browsers to perform the request and receive pattern too many times and slow down your page.
  4. Cached Objects — You want browsers caching your site. You need to instruct the Web server to enable expires headers on your static objects.
  5. Text Compression — If you don’t have text compression turned on, your page is going to be slow. We turn this on by default on our Web Hosting plans, so your if your page is suffering from this, it’s either because of third-party objects, or it somehow got disabled on your hosting account.

You can use Google PageSpeed Insights tool to check your website to see if your web pages fast on all devices or not?

https://developers.google.com/speed/pagespeed/insights/

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