One component of how Google Inc. ranks web sites in natural search listings is site performance, how quickly a site’s pages load. After a recent comprehensive examination of the web, Google is sharing some insights on how site operators can get their pages to load quickly.
— The average page size is 320 kilobytes.
— Only two-thirds of the compressible material on pages is actually compressed.
— In 80% of pages, 10 or more resources are loaded from a single host.
— The most popular sites could eliminate more than 8 HTTP requests per page if they combined all scripts on the same host into one and all style sheets on the same host into one. HTTP requests are sets of commands sent to a server to return data.
It also found that each web page had an average of 43.91 resources and 7.01 unique host names. There was an average of 29.39 unique images per page, with an average size of 205.99 KB each. The average number of external scripts per page was 7.09, with a script size average of 57.98 KB. For style sheets, there was an average of 3.22 per page, each with an average size of 18.72 KB.
Site operators can make changes to improve their site speed, Google says. For example, they could eliminate an average of 3.75 requests if they combined all scripts on the same host, and 2.02 requests if they did the same for external style sheets. For the most popular sites, these figures climb to 4.75 for scripts and 3.54 for style sheets.
“The Google data points out that there is much low-hanging fruit to improve the performance of most web sites,” says Mike Gualtieri, a senior analyst at Forrester Research Inc.