With page speed about to become a ranking factor in May 2021, you need to figure out how to squeeze every last drop of speed out of your website. What’s more, desktop and mobile speeds are calculated differently. Here’s a screenshot of the Core Web Vitals section of my dashboard for my website:
You can see that despite all my experience with speeding up pages, I still struggle to get it right. Caching, optimizing, minimizing, lazy loading, reducing CLS, and more. It’s an ongoing process that I constantly need to tweak to ensure that my pages remain fast. And yet mobile phones remain a problem.
The Unique Challenges of Mobile
Everyone knows that mobile phones take longer to load content compared to desktop pages. And the Googlebot now crawls websites with a mobile crawler as a priority. There are complicated reasons why mobile has slower load times. One of them of course is that the Internet speeds are not as fast. Sure, most devices will be on wifi, but the Core Web Vitals is based on the 75th percentile of views. This means that every person on a slower connection puts your stats in danger.
The second reason why mobile loading is slower is that the mobile browser has to do a lot of effort to resizing the page and its elements to make them fit. This is a particular problem for images. Image processing is a CPU intensive task, and resizing them to fit the mobile viewport is always going to be an issue. The problem is exacerbated by the fact that mobile phones have slower and less efficient processors compared to desktops, and so page rendering times are nothing to sneeze at.
And this doesn’t even begin to touch connectivity problems and coverage issues in out-of-the-way areas, and when a mobile tower has too much traffic. There are just so many different reasons why mobile speeds are slow.
So What Can We Do?
All this might make you think that you should develop a separate site for portable devices. But that’s a terrible idea. I’ve already explained my reasons in the linked article, so I won’t go over them again. But having the same codebase means you can’t do much to speed up traffic specifically on mobile devices.
There are some interesting settings to play around with Cloudflare however. For one, Cloudflare’s “Mirage” technology replaces images with lower dimensions for small screens and lower resolutions for slow connections. I’ve tried out this technology for the past month or so, and it appears to work well. At least it doesn’t slow things down, which was my biggest concern! One caveat, however, seems to be that Google’s debugging tools like PageSpeed Insights don’t treat Mirage images as “lazy loaded” even though they are. Also, the lazy loading from Cloudflare appears to block input for a long time, causing speed tools to complain.
You should test these out for yourself and measure the result to get the true impact on Core Web Vitals.
You can also try Cloudflare’s “Polish” setting which compresses images and uses the WebP image codec if supported by the browser. I optimize my images anyway, so it’s not something I use. But you might find it useful!
Does Blocking Slow Countries Help?
We all know that some countries have really slow load times. Those in Africa are a good example because of the unique Internet challenges that the continent faces. So if you don’t get a lot of paying traffic from these countries, feel free to block them. It works, regardless of what Martin Splitt says. His concern is that people will use VPNs to access your content anyway, so there’s a danger of things getting worse. But if your site is in such high demand that people are willing to use a VPN to access it, I’m guessing you have bigger problems to worry about than a few points on Core Web Vitals!
I’m a NameHero team member, and an expert on WordPress and web hosting. I’ve been in this industry since 2008. I’ve also developed apps on Android and have written extensive tutorials on managing Linux servers. You can contact me on my website WP-Tweaks.com!