The median load time for home pages of the top 500 US retail websites (as ranked by Alexa) continues to slow down, clocking in at 9.3 seconds during the Winter period, 21% slower than the 7.7 seconds from a year earlier, per results [download page] from Radware’s latest E-Commerce Page Speed and Web Performance study. In fact, the top 100 sites were slower than the rest.
With a median load time of 10 seconds, those top 100 sites slowed significantly from the preceding year, when they loaded in a median time of 8.2 seconds. Indeed, half of the sites took at least 10 seconds to load.
The slowdowns are continuing as pages grow in size, with the median page growing by a hefty 31% over the course of the year. Specifically, the median page was 1,436 kb in size and contained 99 resources, up from 1,094 kb and 93 resources, respectively. (The increase in page “weight” was an even bigger 40% among the top 100 sites.)
Median Time to Interact (TTI), a metric introduced in a previous report that analyzes the “point at which a page displays its primary interactive content,” also remains slower than the ideal. The metric is designed to be a key gauge of how quickly a page can deliver a satisfactory user experience, according to the researchers, as well as how rapidly the page can accomplish the site owner’s goals. Among the top 100 e-commerce sites, the median TTI stands at 5 seconds; 26% of the sites took at least 8 seconds to become interactive, compared to only 20% that took 3 seconds or less.
Despite improvement in the number of top retail websites continue employing best practices, these seem to have reached a plateau, according to the analysts. Some 93% of sites have a successful implementation rate of “keep-alives,” while 80% use a content delivery network (CDN), up from 58.4%. Meanwhile, 37% of the top 100 sites failed to compress images, and only 3% used progressive JPEGs. These figures haven’t changed appreciably from past reports.
About the Data: Radware describes its methodology as follows:
“The tests in this study were conducted using an online tool called WebPagetest ”“ an open-source project primarily developed and supported by Google ”“ which simulates page load times from a real user’s perspective using real browsers. Radware tested the home page of every site in the Alexa Retail 500 nine consecutive times. (The system clears the cache between tests.) The median test result for each home page was recorded and used in our calculations.
The tests were conducted between January 16-26, via the WebPagetest.org server in Dulles, VA, using the latest version of Chrome (31.0) on a DSL connection.
In very few cases, WebPagetest rendered a blank page or an error in which none of the page rendered. These instances were represented as null in the test appendix. Also, in very few cases, WebPagetest.org rendered a page in more than 60 seconds (the default timeout for webpagetest.org). In these cases, 60 seconds was used for the result instead of null.
To identify the time to interact (TTI) for each page, we generated a timed filmstrip view of the median page load for each site in the Alexa Retail 100. TTI is defined as the moment that the featured page content and primary call-to- action button or menu was rendered in the frame.”