Web site performance

Last week I read Steve Souders’ High Performance Web Sites. While I already have a fairly good understanding of site performance, having completed a fairly extensive performance analysis of tvnz.co.nz a few years ago and being familiar with Yahoo!’s YSlow plug-in for Joe Hewitt’s Firebug plug-in for Firefox, it was good to get into a bit more detail.

But lately, I’ve come across a few sites that have made me cringe; a colleague pointed out a couple of Swiss ones: migros.ch, and gate24.ch, and I came across the new upandgo.co.nz site on newsites.co.nz.

Let’s look at some stats, with vodafone.co.nz (my old gig) thrown into the mix:

Site YSlow score HTTP requests
(unprimed cache)
(kB, unprimed cache)
(kB, primed cache)
gate24.ch F (40) 55 501 49
migros.ch F (39) 85 996 134
upandgo.co.nz F (35) 77 748 284
vodafone.co.nz B (88) 41 195 23

The first three sites are ASPX sites, with bloated, invalid, (W3C) table-based markup, and what appears to be no performance tuning whatsoever. Sure, they are visually heavier than vodafone.co.nz, but being visually heavier doesn’t necessarily equate to looking better, and more often the end-user benefits of the visual components are offset by the performance overhead they introduce.

So, if you’re a web developer and you don’t use, or know of, Firebug and YSlow, stop what you’re doing right now and get familiar with them. Chris Pederick’s Web Developer toolbar for Firefox is also invaluable.

Learn about ETags, far future Expires headers, gzip, script placement, semantic markup, reducing the number of HTTP requests.

These are all vital factors in presenting a great website.
Figure out what you can do to make your site lighter, faster, and more search engine-friendly.

This entry was posted in Coding, Commentary, Design, Tools, Web Standards. Bookmark the permalink.

6 Responses to Web site performance

  1. Rob Coup says:

    Pagetest is a tool that was opensourced recently by AOL – it does a complete load-time analysis of a URL. It simulates IE6 & IE7 rather than the faster Firefox, and including first-time and primed waterfall charts, optimisation reports, quick-fixes, and you can test from different connection speeds.

    The tool is available at: http://pagetest.patrickmeenan.com:8080/

    Results for http://www.vodafone.co.nz: http://pagetest.patrickmeenan.com:8080/results/3X1/ YSlow on my FF3/OSX gives http://www.vodafone.co.nz a F(59) grade… and it doesn’t look hot on the above test either – maybe user-agent switching is rampant?

  2. robbie says:

    So is it that they are written in aspx which makes them bloated?.

  3. Pingback: two seven » Blog Archive » Does developing in .aspx produce bloated code?

  4. Dan says:

    Wow Rob, that is a very cool tool.

    The interesting thing is that while YSlow seems to test with both primed and unprimed caches on each test attempt, it often gives different results.
    I just ran it again and it gave a D (63).


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  6. Yayat says:

    your pages weights 170KBytes.Dialup cnnoection is 56Kbit/second = ~5KB/second, so it will take 170/5=34+lag= ~40 seconds to fully load this page.If you compare this to broadband 1Mbit/second = 128Kbyte/second it will be 170/128=1.3+lag (lower for fast cnnoection)= ~1.5 seconds to fully load same page on such cnnoection.This is simplification of course. There are many other factors that contribute to load speed so it’s theoretical, while real page size is factual.

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