Page Speed is a Firefox/Firebug – not Chrome, mind you – add-on that Google’s been using internally for some time.  It conducts tests on Web server configurations and front-end code in order to reach its conclusions, and a post on the Google Code Blog explains, "Page Speed’s suggestions are based on a set of commonly accepted best practices that we and other websites implement."

Those best practices are available in written form if you’re feeling curious and would like to inspect them.  The Webmaster Help Forum is standing by if you’ve got any questions.  Also, since Page Speed is an open source project, real go-getters can contribute to its development.

Google’s Page Speed appears to be in competition with Yahoo’s YSlow, which has been available for years.  It’ll be interesting to see which one comes out on top.

Or you can always try both, of course, since (leaving aside the old joke about blank pages) there’s no such thing as a site that’s too fast.

The Yahoo Developer Network release YSlow, which requires the Firebug add-on for Firefox. Once in place, YSlow looks at a site’s performance and stats to determine where troubleshooting should take place.

In the Performance View, YSlow recommends where changes can be made if they are needed. A site that makes a lot of HTTP requests, or doesn’t use a content delivery network for eligible content, would have those sections of the report flagged for review.

Under the YSlow Stats View, the add-on calculates the size of a page for both empty and primed caches. Also, YSlow shows information about cookies the server places on the browser for the page.

A Components View lists all page components by type and other details. Webmasters can view the HTTP response headers for any of those components.

Those who plan to attend The Ajax Experience in San Francisco this week can learn more about YSlow there. A session presented by Yahoo’s Exceptional Performance Team will cover the use of YSlow for performance analysis.