Large diffs are slow and could end up in timeouts when comparing page versions

When trying to view, in Rendered mode, the changes between two versions of Release Notes page (https://www.xwiki.org/xwiki/bin/view/ReleaseNotes/Data/XWiki/15.10.13/?viewer=changes&rev1=1.1&rev2=6.3&), the content never show up, but a 504 error is returned from the server: