Zoompf's Web Performance Blog

Note: Archived Content

This is the archived version of the Zoompf blog. Since our acquisition by Rigor, all our new research and posts on web performance are being published on The Rigor Blog

Web Performance Survey: How Ready Are the 5 Top US Online Retailers for Black Friday?

 Mark Isham on November 25, 2013. Category: Alexa Research, Optimization

With Black Friday just 4 days away, I thought it would be interesting to conduct a website performance survey of 5 of the top US online retailers to see just how ready they are for the upcoming uptick in traffic. And since most sites focus the majority of their optimization efforts on their home pages, let’s try to trip them up by focusing instead on the page where their customers linger the longest: the product detail page.

…And of course if we’re going to pick a product page, why not choose what may be the hottest gift of the 2013 Holiday season: the brand spankin’ new XBox One console!


Page Load Times

To begin our survey, I grabbed the URLs of the product detail pages for the XBox One “Standard” Console from 5 of the Top US Online Retailers: Amazon, Walmart, Target, ebay, and Best Buy. I then plugged these URLs into the visual comparison function of WebPageTest in a manner similar to my blog post back in May racing the Top 9 US Retailers, using the “Visually Complete” time for the finish line (More Information). You can watch the side by side comparison in this following 30 second video:



As you can see, all 5 retailers finished with respectable times, with odds favorite Amazon emerging as the clear winner at a brisk 2.2 seconds:

  1. Amazon: 2.2 seconds
  2. Best Buy: 2.9 seconds
  3. Target: 3.0 seconds
  4. ebay: 4.2 seconds
  5. Walmart: 4.7 seconds

With that said, are these sites as ready as they could be for Black Friday? Using the Zoompf Free Performance Scanner, I took a look at each of these product pages to see what else, if anything, these sites could have done to speed up their sites even further.

1. Amazon

  • Detail Page Link
  • Page Load: 2.2 seconds
  • Zoompf Score: 83 / 100
  • Full Report Detail

Amazon scored quite well both on the page load time and with the Zoompf report, but 9.6% conservative bandwith savings would still be possible through lossless optimization techniques such as minifying 3 CSS files and running PNGCrush on 9 PNG files. Also there are 13 images of the xbox one console that are not cached, forcing the browser to reload them every time the page is reloaded. Caching these would be a quick and easy win to speed up page reloads.

2. Best Buy

  • Detail Page Link
  • Page Load: 2.9 Seconds
  • Zoompf Score: 78 / 100
  • Full Report Detail

There are 2 notable issues in the Best Buy report worth calling out. First of all, while they are compressing their static content (always the #1 performance win in our book), they are not compressing their .svg files. Scalable Vector Graphic (SVG) files are actually represented in text/XML and are thus excellent candidates for compression. Often it’s a simple matter of configuring the web server to also compress these file types. In one case for Best Buy, a 10k SVG file could have been reduced down to 2.5k, or a 75% reduction. (See detail).

The other, more important, issue we found was 118 images that did not use “Far Future” caching as shown here. For static resources, we recommend caching for at least 6 months or longer, using file versioning to accomplish cache flushing if changes are required before the 6 months. In the case of Best Buy, many of the 118 images referenced were cached for 1 month or less, with some cached for as little as 1 hour! This represents a significant amount of unneeded repeat requests from the browser on subsequent page loads, slowing down page load times.

 3. Target

  • Detail Page Link
  • Page Load: 3.0 seconds
  • Zoompf Score: 84 / 100
  • Full Report Detail

The most obvious optimization we found here was the presence of 61 PNG images that could be reduced in size with no loss in visual quality by an average 22%! While many of these images are small, some are as large as 170k and the savings can quickly add up. Furthermore, optimizing these images is super easy using free tools like pngcrush or smush.it. This is a real easy win for little effort.

4. ebay

  • Detail Page Link
  • Page Load: 4.2 seconds
  • Zoompf Score: 78 / 100
  • Full Report Detail

This is kindof funny, as it looks like this ebay seller took their images for the xbox straight from Amazon, which means they in turn suffer the same exact performance problem: 13 images (the very same 13 in fact) are served without caching. We can’t really fault ebay on that one since that is a choice the seller made, but perhaps ebay could mitigate seller behavior like this in the future by hosting seller images on a replicated Content Delivery Network which automatically utilizes browser caching.

Also similar to Target, there are 29 ebay PNG images (e.g. hosted by ebay and not provided by the seller) that could benefit from optimization by an average of 19% with no loss in visual quality using tools like PNGCrush or Smush.It. Since these are ebay supplied images, this optimization would be directly within the control of ebay and could give them a nice reduction in page size.

5. Walmart

  • Detail Page Link
  • Page Load: 4.7 seconds
  • Zoompf Score: 80 / 100
  • Full Report Detail

There’s a big whale of an improvement lingering in the results for Walmart: a full 215 images off the product page are using caching set to expire in 1 hour or less! Click into each link in this detailed report to see the gory details. This is a more extreme version of the same type of issue reported in the Best Buy analysis above.

If you look at the types of images being reported, virtually all of them are standard components of a typical product detail page, in other words they are images that are reused from one product page to the next on the Walmart site. This means every time you visit a Walmart product page, just one hour later you will need to reload all those 215 images again!

Like we mentioned in the Best Buy report, we recommend caching for at least 6 months and using file versioning to update resources when needed. This could result in a significant performance benefit for repeat viewers with very little effort on the administration side.

Furthermore, due to the large # of small individual images on that page, using CSS Sprites to significantly reduce the number of requests could be hugely beneficial, albeit harder to perform. You can read more about CSS sprites in our recent article on Moz: How to Improve Your Conversion Rates With a Faster Website.

There are definitely some big wins possible for the Walmart site that could help them pull up from last place in their top retailer ranking position. If you work for Walmart, drop us a note and we’ll be happy to help you out :-).

In Closing

Black Friday (and the soon after Cyber Monday) is the “super bowl” season for online ecommerce. While its highly unadvisable these sites make any changes to their code this week (I used to work in ecommerce and one lesson I learned well was “don’t touch a thing!” after November 1st), there are some good lessons to be learned here even by the “best of the best” for next year. It’ll be fun to watch how these sites perform over the 2013 holiday season.

If you want to see how your site performs, try our free Website Performance Scanner to learn more about how you can speed up your own site for Black Friday and beyond!


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