Before migrating from Wordpress.com to my GatsbyJS site, I did a website speed comparison using GTmetrix.com which runs PageSpeed and YSlow tests to determine the speed score of a site.
As seen, my Wordpress.com site was not exactly a high scoring blog on the Internet. To be fair, I never did anything to improve the performance of the site.
The new GatsbyJS site performs extremely well out of the box, much better than my Wordpress site. The comparison is not even an apple to apple comparison, since for the Wordpress site, I only loaded a few of the blog posts on the initial load. For the Gatsby site, I generate an Index file containing ALL my blog posts! The latter allows searching on the site using the browser search, which is just plain awesome.
For the Wordpress.com blog, blog posts were lazy loaded as the browser scrolls down. For the Gatsby blog, images are lazy loaded as they are shown. Looks a bit strange, but the responsiveness (as in performance) is a huge win.
The YSlow score could be better, buuut I think I will put that on my endless todo list for another time :-)