What it takes to be fast in your industry
Posted in: Ecommerce   -   September 11, 2012

The holy grail of Web performance seems to be load times of two seconds or less. At the same time I hear people saying that the specific purpose of their Web site requires more and heavier content and consequently leads to higher load times. “I am running a media site, I need more images and videos” or “all our content is highly dynamic that’s why our pages load slower” are phrases typically used to justify higher load times.

If you compare a media site to Google’s search page it becomes obvious that there is a significant difference in the content that is shown.

Google vs. CNN (A big difference in page content)

Google vs. CNN (A big difference in page content)

At the same we know that people get bored or lose their attention when activities take too long. The easiest way to figure out how performance relates to the specifics of an industry site is to test the top sites and look at their performance metrics.

I used speedoftheweb.org to do this and decided to look at three industries which typically have a strong Web presence; retail, travel and media.

Page Timings

First I looked at First Impression Time. Interestingly the median across all industries was about 1.5 seconds.

First Impression Time across industries

First Impression Time across industries

However when I then looked at the Total Load Time the picture was completely different. Media sites were noticeably slower and the slowest pages took up to 23 seconds to load.

Total Load Time across industries

Total Load Time across industries

So where is the time actually lost? To figure this out I created a chart that visualizes the lifetime of page loading. The first time is lost between First Impression and the onLoad event but the by far biggest chunk is lost after the onLoad event.

Page lifecycle time loss across industries

Page lifecycle time loss across industries

What makes pages slow?

Having done quite some page optimization analysis I know that content size and number of resources are typical sources of performance problems. While there is not a big difference among the top pages across industries it is noticeable that the biggest pages are larger by a factor of 5 to 10 times compared to the best in the industry. Big media sites for example require up to 3.8 MB of content. This might create the impression that these pages look very different.

Content size across industries

Content size across industries

However looking at MSN (fast) and CBS (slow) shows that there are not really big difference from the content that is shown.

msn vs. CBS - visual comparison

msn vs. CBS – visual comparison

Performance differences beyond content

The big performance differences however do not come from content alone. Because if this were the case the by far biggest part of the loading time would be on the onLoad event. This made me look at the JavaScript execution time. As speedoftheweb using dynaTrace AJAX technology underneath, it was pretty easy to get this information.

JavaScript time across industries

JavaScript time across industries

While top sites stay around 2 seconds of JavaScript time the top consumers execute over 10 seconds of JavaScript during a single page load. This explains why these pages then take up to 23 seconds to load.

Conclusion

So what can we learn from this exercise? First of all there are differences in performance between industries. At the same time the top pages across industries show quite similar and pretty excellent performance characteristics. So the argument that a site cannot be fast just because of the specifics of it’s industry does not really hold. If you want to learn how your site performs compared to others in your industry try speedoftheweb.org


Alois Reitbauer (@aloisreitbauer) works as Technology Strategist for dynaTrace software and heads the dynaTrace Center of Excellence. As a major contributor to dynaTrace Labs technology he influences the companies future technological direction. Besides his engineering work he supports Fortune 500 companies in implementing successful performance management.

Tags: , , ,