What are cache preloading and APCu for on Faaaster?
Both optimizations are set from the site's Performance tab. Cache preloading spares visitors from being the first to hit a page that isn't cached yet; the APCu object cache speeds up database queries.
Cache preloading
According to the interface: "Prevents some visitors from experiencing slowdowns when a page has not yet been visited."
The server cache only fills up as visits come in: the first person to request a page waits for it to be generated. Preloading does this work ahead of time: when it is on, the site is crawled automatically on every startup to fill the cache. A manual cache purge does not restart this crawl.
APCu object cache
According to the interface: "Improves loading performance by speeding up database queries."
Setting them
- Open the site, Performance tab.
- In the Cache section, turn on APCu object cache. Cache preloading is on by default; its switch lets you turn it off.
These switches are reserved for the Owner, Admin and Member roles.
Turning on APCu
APCu must be installed in the environment before it is active: after you turn it on, its status goes through an installation phase before it becomes operational. Allow a few moments, then refresh the screen.
If the option stays unavailable, your server environment is too old to support it. Update it from the Server tab, Server environment row, then come back.
Which one should you turn on first?
Preloading, if your site is a showcase site or a blog: it removes the wait for the first visitor on each page.
APCu, if your site queries the database heavily — store, catalog, members area. It adds nothing to a site that is already served entirely from the page cache.
Turn them on one after the other, and check the measurements in between: the Performance tab for response time, the Monitoring tab for resources. Two simultaneous changes will keep you from knowing which one produced the effect.
👉 How do I monitor my site's performance? · Should I turn on the managed cron?
Updated on: 10/03/2026
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