When it comes to measuring site speed, the only metrics you should really be focused on are Google's Core Web Vitals. These are the only metrics that reflect the actual user experience on your site, and the only ones that actually impact Google's search engine rankings (even then, Google have said themselves that the impact is minimal compared to other factors such as the relevancy of your content and the unique value it provides).
As such, Ezoic's technology is geared towards improving your Core Web Vitals. This can sometimes come at the expense of outdated metrics used by third-parties to determine your site speed, including Google's own PageSpeed Insights scores.
These metrics are often erratic because they are easily influenced by factors such as Ezoic's "lazy loading" of ads, which is where ads (particularly those below the fold) sometimes take a few seconds to load. We do this because we have found from testing with tens of thousands of sites that serving ads as quickly as possible isn't actually very good for user experience or revenue. Instead, we've found that it's better to stagger the loading of a page to ensure that the user receives the content first (i.e. the aspect of the page they came to the site for) - this way, the visitor can begin interacting with the page immediately, whilst other elements of the page (i.e. ads, click/like buttons) load in the background. This is what we call "Lazy Loading" and is recommended by Google themselves to help with your Core Web Vitals (remember, these are the only metrics that Google actually care about).
It's also worth bearing in mind that only Ezoic is able to optimize your site effectively for Core Web Vitals thanks to our server-side integration options i.e. cloud integration whereas most ad networks use JavaScript-based or client-side integration, which is much slower.
Whilst some of these optimizations are done behind the scenes, you also have control over many of these via our Leap app, which is free-to-use.
In summary, adding in a more complex ad set-up is almost always going to have some sort of impact on your site speed, however Ezoic's technology not only mitigates for this, it actively addresses many of the other factors that negatively impact your site's Core Web Vitals, boosting user experience as well as revenue.