This article is to help explain the benefits of page caching and provide some examples with and without along with CDN based page caching. There is many different kind of cache but this will focus on specifically page caching which you may also also heard a reference to caching your HTML. When you visit your site without any page caching, this means WordPress needs to use PHP to dynamically generate all the content you see on the page, this includes having to pull all the data from the database, all of these things take time regardless of how fast your hosting is.
The huge key benefit of page cache is it takes a snapshot of this dynamically generated page and creates a single HTML file which is then served to your visitors so instead of them waiting on the server to talk to the many different areas to generate the page, it will give them a single pregenerated version of the page which requires next to no server resources to display them.
Lets start of with some examples to show you how long it takes to load a page with and without page cache.
Here is without any page cache:
The very bottom line is the initial resource that loads from your browser, this is often referred to as the server response time. The importance of this initial load time is it effects the entire rest of the site as no other resources will start to load until this completes so the faster the server response time, the faster your site will load overall. You can see it took almost 600 ms without any page caching as the page was dynamically generated.
Now we can load that very same page however this time we will use our server side BigScoots FastCGI caching.
You can see now that the server response time has dropped down to 65 ms this is a huge improvement. To give you an idea of how this affected the overall page load time, please check the comparison below:
Without page cache:
With page cache:
Now as good as our built in caching is, it does lack one ability which is the ability to serve that cache from a location closest to your visitors regardless of where in the world they are viewing your site from.
The further away you are from our data center location, the higher the round trip time there will be because of the distance that needs to be traveled from that visitors location. This is where one of the biggest benefits come from our Enterprise partnership with Cloudflare which gives us the ability to offer page caching on Cloudflares Enterprise network. This will ensure your page cache is now served from a data center closest to them, this can greatly reduce that round trip time in some cases by seconds.
Here is a quick example testing from Germany using https://www.webpagetest.org/
Without any page caching:
We have a 986 ms server response time.
With BigScoots server FastCGI page caching:
It now drops down to 714 ms but due to the distance between that visitor and the data center there is still a large delay.
With BigScoots Cloudflare Enterprise page caching:
We now drop down to a 203 ms server response time!
The response time will always vary depending on many factors but this gives you a good idea on the benefits of page caching along with CDN based page caching.