Usability Tools Podcast: The Truth About Page Download Time

Jared Spool

September 24th, 2007

UIE Usability Tools Podcast: The Truth About Page Download Time
Recorded: September 20, 2007 from the studios of UIE
Brian Christiansen, UIE Podcast Producer
Duration: min | File size:
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Each week in our Usability Tools Podcast, I will be sitting down with UIE’s Managing Director, Christine Perfetti to discuss tips and tools for improving your site’s user experience. The goal of our weekly podcast is to share some of the most important findings from UIE’s research on web design and usability.

This week, Christine Perfetti asked me about User Interface Engineering’s groundbreaking study on download time. In this study, we found the actual download time of a page didn’t impact a site’s usability. In this podcast, Christine and I discuss:

» What users *really* mean when they say a web site is too slow
» User Interface Engineering’s methodology for conducting the study on download time
» The strong reaction of the design community to UIE’s findings
» UIE’s shift in perspective regarding download time due to the prevalence of high-speed connections

As always, we’re very interested in hearing from you. Do you have questions or comments about this episode? Do you have suggestions for future episodes? We want to know. Please leave a comment below or email us directly at

UIE’s Latest Research: If you’re interested in the topics Christine and I discuss in the podcasts, I highly suggest you sign up for our free newsletter, UIEtips, to read our latest usability and design research as soon as we publish it. [We first published our download time findings in UIEtips.] We’ll also notify you in UIEtips when we publish new podcasts.

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19 Responses to “Usability Tools Podcast: The Truth About Page Download Time”

  1. Peter Van Dijck’s Guide to Ease » Blog Archive Says:

    […] Users rate some sites consistently slow and other sites consistently fast. For example, is rated slow. But when looking at the data, the sites that were rated slow weren’t all really slow. Amazon is rated as fast, and it isn’t really that fast (fast enough, but not crazy fast). So why do users feel some sites are slow or fast? ( loaded faster than in the test, yet was perceived as very slow.) […]

  2. Alexander Says:

    Measuring the time that the Netscape logo throbs may be misleading if a page is presenting you interesting content even though it has not completely downloaded. I wonder: if the interns went back through the hours of video (ha ha!) to time how long it took for some meaningful content to appear on the page… (rather than how long the Netscape logo spun). Do you think it would show any differences?

  3. Jared Spool Says:

    Alexander, great question.

    We don’t have to ask the interns to re-watch the video because they got those numbers already on the first pass. (I just didn’t mention it in the podcast.)

    Turns out loaded in a single burst, coming in on average at 8 seconds per page.

    Amazon, as you suspected, loaded incrementally, with the first page full loading long before the 34 seconds it took to load the average page.

    But here’s the kicker: the first screenful on Amazon took 11 seconds to load. It was still 3 seconds slower than the entire page for Yet, users consistently rated Amazon to be much faster than

  4. User First Web » Speed of Site and Usability Says:

    […] and Christine Perfetti discuss a study on how web page speed impacts usability on their latest Usability Tools Podcast. Because this study conflicts with some of the research that I cited during my recent presentation […]

  5. User First Web » links for 2007-09-25 Says:

    […] Usability Tools Podcast: The Truth About Page Download Time » UIE Brain Sparks (tags: usability speedupyoursite) […]

  6. Steve Fisher Says:

    Alexander brought up the point that I was wondering. I’ve seen a number of sites that get slowed up because they are downloading banner ads and the like first, which can greatly lengthen the amount of time it takes for the actual content to show up. I see those sites as slow, but would be curious to see the time differences with those sites and sites as I judge as normal or fast loading.

  7. Tom Philo Says:

    Complete page load times is not the same as the time to start showing something useful to the user.
    The incremental loading of items – including secondary menu graphics and lots of items below the fold, or high res graphics loading after all the text has been loaded, change the perceptions of how fast a page loads. This is where a good designer along with a good technical programmer of web pages can fool the person into thinking a page is faster than what is is by just giving the user something to start scanning (and if they are really interested reading) on the page.

    When everyone was using dyamically sizing tables to layout pages with unsized graphics that was the worse – eveything had to come down before anything was seen due to the way tables are designed to be rendered by the browser.

    Most sites now-a-days will ensure that text is rendered (delivered) first with graphics coming down last into a predefined sized zone with defined placement so the browser does not have to figure out where to put it on the fly – but is told where to put it and thus save time.

    Course not all rules are to be followed – I have some hugh photos on my site so page load is going to be slow – but the people want to see the photos (else the words have no context when comparing aircraft, parts of castles, flowers, people etc) so you ensure that by the time they can read the text the graphics are there.

  8. Torrential Web Dev Says:

    Benchmarks, Site Speed and User Experience…

    Following on the back of my recent posts looking at the (hopefully) best and worst of benchmarks I thought it would be useful to finish off with some genuine tips for creating ‘lightning fast’ websites. I probably lack the experience and insight to …

  9. Mendy Ouzillou Says:

    Very interesting podcast. Like anything though I think there is a balance between focusing on useability and download time. I see many sites that have really long download times because the images have not been compressed properly to a manageable size. Also, I think people tend to focus on download time because that is an easily measurable metric. Useability, as important as it is, is difficult to properly quantify. So … are there any tools that would help me mimic how people experience my glass art jewelry site (lots of images) on a 56k modem? Also, I’d like to see the order in which my content downloads. Any tool for that?

  10. | The Truth About Page Download Time Says:

    […] A study has shown a site’s download time doesn’t seem to impact on a site’s usability. Instead, sites that are easy to use, fun and professional are perceived as being fast. Apparently, people perceive time to take longer when they are in pain. Source […]

  11. Download Time and E-Learning » UIE Brain Sparks Says:

    […] wrote: I just listened to your podcast: Usability Tools Podcast: The Truth About Page Download Time. Can you express your thoughts on download time and usability as it applies to e-learning modules […]

  12. Czas ładowania się strony « O użyteczności zwanej też usability Says:

    […] Więcej w The Truth About Page Download Time […]

  13. Kinjal Says:

    Do you guys think that streaming results like where there is a perceived notion of fast page load help in maintaining users expectations?

  14. Jared Spool Says:


    I think that using Ajax to make a page more responsive is often a good thing.


  15. Steve Souders Says:

    When I first started my work on web performance back in 2004, I came across Christine and Lori’s article about this experiment. I found it fascinating, even though it contradicts what I evangelize.

    Here’s the important takeaway: It’s not all about speed, and it’s not all about design. Both of these areas, along with others (uptime, bugs, security), affect user perception. The challenge for web developers is to figure out where to focus right now. That’s why I created YSlow – so web devs could easily see if they had performance issues. It’s harder to quantify this when it comes to design.

    We know that speed affects users, as evidenced by the many studies presented at the Velocity conference. Trying to determine which factor is most important for a web site is like asking what’s the most important repair to your house – it all depends on the current state and which areas are strong and which need more shoring up.

    Keeping all other things constant, it’s been shown that making a web site faster improves user metrics. It would be fascinating to hold performance constant, and see how changing the design affects user metrics. I’m sure user metrics would improve, but by how much, and how could we trade that off against possible performance improvements.

  16. Defining Download Time: Web Searchers Vs. Search Engines Says:

    […] What do users really mean when they say a web site is too slow? Jared Spool did a follow-up podcast on this subject at: Usability Tools Podcast: The Truth About Page Download Time. […]

  17. Psychology and Web Performance: Some quick facts and ideas — Web Performance Today Says:

    […] a fascinating study (and podcast) that claim ‘the truth about download time’. The findings were that when people […]

  18. Performance Calendar » Blog Archive » Psychology of performance Says:

    […] a fascinating study (and podcast) that claim “the truth about download time”. The findings were that when people […]

  19. Killer Secrets to Increasing the Speed of Your Blog - Blogging Tips Says:

    […] be a site that takes too long to load, but you’re wrong to an extent. The studies discussed in this podcast episode show that it depends more on how the user perceives your site load speed rather than your actual […]

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