Load WP content with ajax less server demanding and faster than normal page loading?

Question

This is a technical doubt I had after reading some articles about WP ajax process (cannot find them though).

Is it faster and cheaper to load WP content (any content, page, post, widgets etc...) using WP ajax API than making a full canonical page request?

I thought about this because maybe passing through wp-admin/admin-ajax.php is lighter than loading a new page running the whole WP stack altogether.

Am I right?

Answer 1

No. Let's compare.

Normal load:

1. Access URL.
2. Load WP core.
3. Retrieve stuff from database.
4. Load template file.

Ajaxy load:

1. Accesss URL.
2. Load WP core.
3. Load template file.
4. Load JavaScript.
5. Make Ajax request.
6. Load WP core (again).
7. Retrieve stuff from database.
8. Receive stuff from Ajax.
9. Put into page.

Repeat steps 5-9 for each Ajax request.