Core Web Vitals and Other Metrics: More of the Best and Worst Examples

Carrying on with our first part series of the best and worst websites for Core Web Vitals and the broader website metric landscape, let’s dive into more of the current champions and chumps of website performance.

So let’s crack on with even more of those websites at the forefront of site performance as well as those that are seriously lagging behind – when it comes to website metrics.

Render Blocking Resources

Render blocking resources are JavaScript and CSS files which are loaded before the rest of the page. In most cases, these files are not required to display the first paint of a webpage.

The champion

When it comes to the best performer of Render Blocking Resources, top of the class is the Chicago Tribune. Despite many online newspapers and magazines struggling with slow loading times, the Chicago Tribune manages to buck the trend and has eliminated almost all of its Render Blocking Resources.

Last place

When it comes to the bottom of the class, the poorest-performing student is luxury car manufacturer Lamborghini. They would manage to save 2.8 seconds of page loading time by getting rid of Render Blocking Resources. Yet with heavy videos and images across its site, the fast car manufacturer ironically has the slowest site.

DOM Size

DOM stands for Document Object Model and is the sum total of all objects that are part of the HTML structure. The more elements, the bigger the size and the slower the site speed.

The champion

When it comes to the best performer of DOM size, top of the class is PayPal, which holds less than 300 DOM elements. In comparison, the top 20 average has 2,355 elements.

The slowest

When it comes to the slowest sites out there in terms of DOM size, the NHL has a homepage of over 12,000 DOM elements. And this results in slow loading experiences with its excessive media assets.

Image Metrics

The champion

When it comes to the best in class in terms of image metrics, the fastest is the Poetry Foundation. This is a great example of a website that uses multimedia content while scoring well in all three image metrics (responsive, load time, optimized). It uses a WebP image format to keep size low and quality high. It also optimizes image sizes for mobile.

The slowest

In terms of the worst in the class for image metrics, it is the website of the NBA. The image-heavy site is not optimized for size nor mobile devices. There are actually some cases where, by reducing image size and converting them to next-generation image formats, it would suppress page load times by 20 seconds.

Unused JavaScript

The champion

When it comes to the best in class, there is no better than IMDb. The online database for all things film and TV doesn’t load anything that is not needed. And like Wikipedia, it has one core layout for its pages, keeping JavaScript to a minimum.

The slowest

The slowest in the JavaScript class is the Bleacher Report, which uses JavaScript for loading dynamic content, which includes the loading of scripts that can display Tweets. And this load even when there are no Tweets to show. Unfortunately, the Bleacher Report is a typical example of bloated code.

Unused CSS

On average, websites can save approximately 100 milliseconds in page load time if they optimized CSS.

The champion

When it comes to the best in class who has cleared most of its unused CSS, the best is the How-To Geek website. The tech tutorial site performs very well despite using dynamic ads and plenty of media assets. Most of its pages don’t have unused CSS rules as it goes with a one size fits all approach.

The slowest

It may be one of the most trusted sources of news in the world, but its website is also the most bloated when it comes to unused CSS. And this is BBC News. Many of its pages would be able to save between 1.5 and 2 seconds by just loading CSS stylesheets that are needed.

PS: ArganoUV is one of the world’s leading Core Web Vitals teams. Contact us to see how we can work together.