About one year ago, i wrote about the compared performance of WPML, qTranslate and Polylang. Of course I cannot test every multilingual plugins as there are now quite a lot on the market and thus decided at that time to focus on the two most widely used plugins.
However, over the past year, I read a lot of blog posts praising the benefits in performance (speed) of multilingual plugins relying on WordPress multisite feature. Here are some quotes found on the internet about Multilingual Press:
Use WordPress’ built-in core features to create networks with multiple languages without losing any performance.
Performance. This plugin uses WordPress’ built-in core features. For large WordPress sites is the best option.
One pro is the performance: single site plugins must use custom post types, they have to filter almost any database query to get the correct languages. This is slow, much slower than a simple switch_to_blog() behind the scenes.
It doesn’t harm your website performance.
But unfortunately, none of these assertions come with facts. I am curious and wanted to know more, and so finally decided to compare the free version of Multilingal Press 2.1.2 to Polylang 1.6.3.
I used exactly the same test protocol as last year except for the version of WordPress (4.1 instead of 3.7.1). Note that WordPress alone and Polylang are tested on single site installations, whereas Multilingual Press is obviously installed on a multisite installation.
Here are the first results when querying the English version (no .mo file is loaded). Figures reported are average total time per request in ms:
|Non localized (en_US)||WP alone||Polylang||Multilingual Press|
Below are the results when querying the French version (the French .mo files are loaded including for the site with no plugin for which the language is set to French in the WordPress general settings):
|Localized (fr_FR)||WP alone||Polylang||Multilingual Press|
And here is a simple table to summarize the performance impact of Multilingual Press and Polylang compared to a fresh WordPress (single site) installation.
The first conclusion of this test is that the performance of WordPress itself has decreased quite a lot in one year! Just compare the figures with those obtained one year ago for a WordPress installation without any plugin. Yes I remade the tests with WordPress 3.7.1 to check!
The second conclusion is that the performance of Polylang has neither improved, nor decreased in one year.
The third conclusion is that Mutilingual Press is certainly more performant than qTranslate or WPML, but relying on the multisite feature of WordPress does not give it a significant advantage. And in fact, it seems that Polylang takes more advantages of “builtin core features” – although not the same – to get a significantly better performance.