User blog comment:MisterWoodhouse/The first migrations to the Unified Community Platform/@comment-47120596-20201219190623/@comment-1038387-20201219200022

That is defintily true; the visual editor takes a while longer to laod and the Source Editors as well. Even with the toolbar switched off, the 2010 Source Editor is the fastest load, but it's still slower than the 2006 Source Editor. However, that editor is no longer compatible with the current versions of MediaWiki.