The Google PageSpeed Insights rating and WP Rocket optimization

So, you head over to Google PageSpeed Insights, because that’s what all the articles tell you to do, and enter your URL. You will be presented with a rating and a list of recommendations from Google. At this point, you’re appalled:

• “What are all these red and orange warnings?”
• “Why is my grade so low?”
• “What do all these recommendations mean?”

After adding caching to your site, you may expect your PageSpeed rating to be near perfect. Or, you’re studying the recommendations and wondering why your caching plugin didn’t resolve them all automatically.

Many customers wonder why their PageSpeed rating isn’t higher, or they assume that because it doesn’t increase much, it means that WP Rocket isn’t doing much.

The simple reality is this:

Your Google PageSpeed score doesn’t matter. Here’s why.

The need for speed

WP Rocket aims to make your site faster.
Speed, i.e., the loading time of your site is the most important metric. This is what matters for user experience and for SEO. When the Google bot crawls your site, it can’t see your “rating”, only your speed.

Compare to the figures delivered by google console and/or the excellent Pingdom Tools

Think back to your schooling. Did the perfect grades mean you were smart? Not necessarily. It simply meant that you passed your checks. But many intelligent people are not very good on exam days…

So, just as school grades aren’t an indicator of intelligence, Google’s PageSpeed grade isn’t actually an indicator of speed.

Here are 3 websites that all have similar load times, but with wildly different PageSpeed scores:

LOADING TIME: 596 MS
GOOGLE PAGESPEED: 70

Between these 3 sites, the loading time is between 465 ms and 596 ms, but the PageSpeed score varies between 58 and 91.

And the site below has a very good PageSpeed score but is slower than the previous 3:

So you can see from these examples that the Google PageSpeed rating is not a speed indicator.

Hunting for certain parameters is a waste of time

No site gets a perfect rating. In fact, it is almost impossible to obtain. If you try to reach 100/100, by applying all the suggestions of Google PageSpeed, you will quickly lose your sanity.

You can’t take all of Google PageSpeed’s suggestions literally, as they are sometimes unrealistic or impossible.
For example, the tool tells you to shrink or add expiration headers to a file that isn’t hosted on your website. That’s impossible. In the example below, only Facebook and Google can add browser caching to these files themselves.

If you use a CDN on your site, PageSpeed may give you a lower score, but in many cases, a CDN provides better speed to your international visitors.
Or if it sticks out to you because you could save 1KB by compressing an image (see below), it’s not worth worrying about!

Render-blocking Javascript and CSS

A common recommendation that PageSpeed likes to make is the following:
“Eliminate render-blocking JavaScript and CSS code in above-the-fold content.”
This recommendation then provides two parts to this recommendation:

1) Remove render-blocking JavaScript

For optimal performance, it’s best if JavaScript files are loaded in your site’s footer or asynchronously, so they don’t block other elements of your site from downloading, which slows it down. But what Google doesn’t take into consideration is that sometimes it’s not possible to load everything in the footer, especially if you’re not a developer and you’re using a standard WordPress theme.

If you have enabled JS minification in WP Rocket, starting with v2.6, we automatically detect whether JS files should be loaded in the header or footer, based on how their developer queued them.

Therefore, if you see the mention “remove render-blocking JavaScript”, it means that some JS files are still loaded in the header. But it may have been intentional on the part of the theme or plugin developer. Sometimes, when you move JavaScript files from the header to the footer, you may break some of your website’s functionality.

So, if you want to improve your PageSpeed score, you can try using this option in WP Rocket’s advanced options:
“JS files should be included in the footer during the minification process” and enter the original full URLs of your JS files. .

Or, if you don’t shrink the files but just want to defer loading, you can use the option:
“Lazy loading JS files”:

if it doesn’t break any functionality of your site, it can help your PageSpeed score.
Also, consider testing the effect on your site’s speed.

2) Optimize CSS delivery of the following

WP Rocket doesn’t have an option to load CSS stylesheets in the footer, as then your site would load without any style, making it broken and providing a deplorable user experience.

Google suggests that you can ” Optimize CSS delivery .”

They basically want you to separate the CSS needed to render the first part of your page and embed it directly into your page’s code, rather than the main stylesheet.

So, as you can see, if you’re not a developer, this task is quite difficult to do and involves recodifying parts of your theme. It also varies from site to site, so it’s not something that can be turned into a one-click solution in a caching plugin.

If you’re a developer or have one, you can ask them to implement this technique. This won’t necessarily improve your overall page load time, but it will increase your PageSpeed score and might seem to load faster, as the elements at the top of the page will load faster. This type of micro-optimization is used by sites like Amazon, where a 10ms difference can affect their results. For most small sites, the impact is unlikely to be large.

So, what is PageSpeed used for?

Google PageSpeed can be useful as long as you don’t treat it as a panacea.

Sometimes, it can alert you to problems that you can fix on your site. For example, it can alert you to the fact that your content is not being created under GZIP. WP Rocket adds the rules for GZIP by default. Therefore, if PageSpeed warns you, it may indicate that your server has not enabled it.

It can also alert you that you have too many large images that can be compressed. This is a good recommendation that you can actually act on by compressing your images before publishing them or by using a dedicated plugin like imagify or whatever.

This is the easiest source of savings on loading time to address and the impact on the display is immediate.

So, it’s best to think of PageSpeed as one of the many tools in your arsenal that can provide you with insights, but your goal should always be to improve your actual speed, not your “PageSpeed” rating.

PageSpeed Usage Instructions

• Don’t blindly trust Google PageSpeed or take it literally.
• Always read the recommendations carefully and assess whether they are possible and worthwhile. If it asks you to do something impossible, you should ignore it!
• Remember to always focus on speed and don’t worry about chasing a note.
• Always use a real speed test tool such as Pingdom to know the impact of any changes made to your site.

To read

How to Properly Measure Page Load Time on Your Website