WordPress performance

How to achieve high performance in WordPress?

Item	Tool	Speedup
Infrastructure	CPU, disk, web server, PHP (OPcache) and DNS	Overall performance
In-memory object cache	Redis, Memcached, APCu	options, post, post meta etc.
Plugins for administration (backup, DB cleanup)	Use WP-CLI instead	Degrades performance
Theme and plugins	Cache-aware ones using object cache or transients
Translations	tiny-translation-cache	.mo file parsing
Navigation menus	tiny-nav-menu-cache	wp_nav_menu()
Post content	tiny-cache	the_content()
Template output	tiny-cache	get_template_part()
Widgets	widget-output-cache plugin	dynamic_sidebar()

This list concentrates on WordPress core generating HTML code. Frontend loading (full page cache) is another topic.