Bandwidth is not the bottleneck

Google’s Urs Hölzle gives the following world-wide average statistics regarding internet use.

  • Average page load: 4.9 seconds
  • Average page size: 320 kilobytes
  • Average bandwidth: 225 kilobytes/second

If bandwidth were the only limitation, the average page should load four times faster using the average bandwidth. The internet protocols that have served us remarkably well were designed for very different usage scenarios. Hölzle says that web pages could load between two and four times faster if we make slight changes to infrastructure protocols and their implementations.

(Sam Savage would point out that you can get into trouble using averages as we did above. When you have variable quantities X and Y, the average of X/Y is not simply the average of X divided by the average of Y. But the calculations above are accurate enough for back-of-the-envelope estimates.)

7 thoughts on “Bandwidth is not the bottleneck

  1. When I last measured page load times for my sites, the slowest one was the WordPress blog with a lot of gee-whiz-bang widgets. The Postrank widget added several seconds to page load times.

    It turned out that it wasn’t quite so bad. The main content and images loaded fast enough. On the sidebar, though, there was a throbber visible for a while before the Postrank data was loaded through some Javascript. Arguably, humans would categorize the page as “ready” even though the Postrank widget was still loading.

    So, when measuring page load times, it’s a good thing to try first define when would you consider the page “ready”. The browser’s measurement might not match the user’s experience.

    (As a sidenote, I did end up deleting that widget in favor of some static content, just in case).

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