The real causes, ranked.
IMAGES
The largest cause by a wide margin. Uncompressed photographs straight from a camera or phone.
A single unoptimised image can exceed the size of an entire well-built page.
NO CACHING
Every visitor causing the site to be rebuilt from the database.
TOO MANY PLUGINS
Each adds scripts, styles and database queries.
THIRD-PARTY SCRIPTS
Chat widgets, analytics, social embeds, advertising.
Each one is a request to another server you do not control.
AN OLD PHP VERSION
Newer versions are substantially faster. Upgrading is frequently the easiest gain available.
A BLOATED DATABASE
Years of revisions, spam and orphaned data.
THEME QUALITY
Some themes load enormous amounts of code regardless of what you use.
WHAT IS RARELY THE CAUSE
The server, on a well-configured host.
If everything else is wrong, a faster server hides it briefly.
