Improving Template Loading for Classic Themes in WordPress 6.2 Could Have Major Impact on Performance

WordPress’ Performance Team recently conducted a core performance analysis to identify and prioritize areas for improvement. The team tested a classic theme and a block theme configured with the Theme Unit Test data, uncovering numerous performance issues. The first priority identified for improvement is template loading for classic themes, as a majority of websites still use the classic theme architecture. The most expensive process in the classic theme tested is related to locating and rendering template parts, accounting for approximately 30-60% of the entire server response in the test results. The second recommendation is to improve translation loading, as more than 56% of all WordPress websites are using translations. The other three priorities include improvements for block-powered sites, with the first two ringing up as the most costly operations in terms of performance. The Performance Team is considering making the tooling for performance profiling more broadly available so other contributors can extend their work.