Permalinks: site.com/post-tite vs site.com/post-id/post-title for SEO and Speed

Question

What are the differences, in terms of overall "work" required by the PHP processor to retrieve a page using these two permalinks settings:

/%post_id%/%postname%/

vs

/%postname%/

The second example has been widely adopted and used for the "SEO" benefits of having a clean, keyword friendly URL.

The first example, which feeds WordPress the post id, is thought to be more efficient on the PHP processor since it does not have to look up the post-id from the post-title. This should not be an issue on smaller sites, the thinking goes, but on larger sites, it could play a significant role.

The first example has been suggested as a happy medium between efficiency and overall site speed and SEO. Is this true?

Answer 1

When 3.3 rolls out (scheduled for later this month), the issues with /%postname%/ have been fixed. The performance issue shouldn't be part of the factor. If you prefer /%postname%/use it.

Link: http://core.trac.wordpress.org/ticket/16687