The document discusses the importance of front-end performance optimization for web pages. It provides 14 rules for optimizing front-end performance, including minimizing HTTP requests, using a content delivery network, gzipping components, and others. Case studies show front-end optimizations can yield 40-50% performance improvements. Research found the percentage of users with empty caches is higher than expected, so pages should be optimized for both primed and empty caches.

1. High Performance Web Sites 14 rules for faster pages Steve Souders Chief Performance Yahoo! [email_address]

3. The Importance of Frontend Performance Backend = 5% Frontend = 95% Even primed cache, frontend = 88%

4. Time Spent on the Frontend 95% 97% youtube.com 88% 95% yahoo.com 88% 80% wikipedia.org 86% 96% myspace.com 95% 97% msn.com 64% 86% google.com 92% 98% ebay.com 92% 81% cnn.com 86% 94% aol.com 86% 82% amazon.com Primed Cache Empty Cache

6. 14 Rules

12. Browser Cache Expt Results 40-60% ~20% page views with empty cache users with empty cache

17. Ten Top U.S Web Sites 139K 178K 106K 205K 221K 18K 275K 502K 182K 405K Page Weight 9.6 sec 5.9 sec 6.2 sec 7.8 sec 9.3 sec 1.7 sec 9.6 sec 22.4 sec 11.5 sec 15.9 sec Response Time D www.youtube.com A www.yahoo.com C www.wikipedia.org D www.myspace.com F www.msn.com A froogle.google.com C www.ebay.com F www.cnn.com F www.aol.com D www.amazon.com YSlow Grade

18. Strong Correlation total page weight response time inverse YSlow grade correlation(resp time, page weight) = 0.94 correlation(inverse YSlow, resp time) = 0.76 correlation(inverse YSlow, page weight) = 0.59

21. Steve Souders [email_address]