I've just made my slides from Performance in Drupal 7 available. There's also video at archive.org

I presented a general overview of performance changes in Drupal 7. This included API changes already made to enhance performance and scalability, some comparison benchmarks between Drupal 6 and Drupal 7 (good and bad news there), and work currently going on to improve performance for both logged in and anonymous users.

Despite some improvements in certain areas and the promise of more, there's also several pain points in Drupal 7 - the most dramatic being node_save() - which appears to take four times as long as it did in Drupal 6. We've still got time to find and fix these before release though, so If you want to help build on the progress we've made so far (or stop us backsliding), places to get stuck in are listed at http://drupal.org/node/367257

I also co-presented three sessions at DrupalCon.

Fen Labalme has posted slides for Quality Assurance and the Drupal Development Process. Videos are also available for Taxonomy Revisited and Usability Testing of Drupal 7 at the University of Baltimore.

Our findings from Baltimore are all posted on drupalusability.org - it's been great to see activity in the core issue queue trying to fix some of these.