Drupal 7 performance

I would like to share two modules that help a lot with Caching for authenticated users on a website.

Authcache Actions

Is a “Rules” - based module that provides action to clean cache for users with multiple roles for a specific page. Simple instrunctions on how to use this module can be found here Read.me

Why should I use this module?

Which is faster? Which scales better for large sites with a lot of data and traffic? If Pressflow 6 is faster, is the difference significant enough to consider building a new site with it? I've heard that D7 was slower initially, but there have been improvements more recently that closed the gap.

Hi guys,
I figured this is probably the best place to discuss Drupal 7 performance for sites in shared hosting environment.

I installed a D7 site on godaddy servers the other day and am puzzled with my page load times. Most significantly it seems that latency is the biggest problem but as I am not necessarily the most knowledgeable on that subject I'd like to get some opinions from other members.

I did all I could to improve my site and it scores 95 with page speed and 91 with Yslow. One would expect a pretty fast site with those scores right? But page load speeds are rather on the slow side.

Dear Drupal community,

We would like some advice and maybe further collaborations regarding a Drupal-based project, specifically concerning performance issues.