I come across this question on benchmarking WordPress in almost every optimization project I work with. So, here is a quick post to make the answer available to everyone (who might ask this question in the future).
Benchmarking can be done in two areas. Firstly the server benchmarking. It is the ability of the server to manage N number of concurrent visitors to the site. The other is application (WordPress) benchmarking. It depends on how quickly it can generate a complete webpage for the server to serve the visitor.
A site that loads in 5 seconds from a test location in New York, USA may not load in the same speed when tested from London, England or when tested from a location in Australia. Before testing the speed of the site, please make sure to do the following tests. These are the very basic tests that do not need any technical know-how to analyse the results.
What does it do?
It checks if your host has enabled compression of HTML, CSS and JS files.
Why do we do this?
By compressing the data (HTML, CSS & JS files), the speed at which the browsers receive the data is increased. In short, compressing resources with gzip or deflate can reduce the number of bytes sent over the network.
Most shared host providers have not enabled compression. Even some of the managed-VPS providers have not, either. So, this is probably the first thing I do whenever I get to the root of the server.
Where do we test this?
HTML Minification Test
What does it do?
Checking if the HTML code is minified.
How does it differ from compression?
Good question. Minification involves removing blank spaces, un-necessary new lines, etc. Compression is better explained here and above.
How to test?
In your browser! For example, open your website in Google Chrome, then right click on the page, then click “View Page Source”. If you see a lot of blank lines, it means it is not minified.
Minifying HTML can reduce the readability of (only) the source code. It doesn’t affect the front end in any way. A normal visitor doesn’t even care about what the technology we use to run the site. A web geek does!
CSS & JS Minification
Both deserve a post of their own. To do a quick check, “view page source” of your website on Google Chrome (or Chromium), then search for the term, “.css” (without quotes). The search box would show you how many CSS files are currently being used. If the minification is already done, the total number of CSS files should be just one!
Speed and Stress Test
Literally, there are hundreds of ways we can test a site’s speed and its ability to serve concurrent visitors. The following list of sites might come in handy. Every site differs greatly in the way they access the load time. So, the results from each of these can not be compared to the real-time user experience or feedback. It is recommended to stick with just one or two to get near consistent results. The list is provided in alphabetical order. I personally recommend WebPageTest.org to analyze various aspects of the site and Blitz.io for stress test.