Despite huge advances in mobile Web browsing, most users remain frustrated by the slow speed at which Web pages are delivered on their smartphones.

If you remember browsing on a mobile phone several years ago, it was a brutal experience. There was no effort to render a page the way it would display on a PC. In fact, the strategy was to strip out as much formatting as possible and render the text and basic images to allow the user to get the content of the page, but not the presentation. That changed in 2007 with the iPhone. Web pages could be rendered very close to how the desktop did it and, with zooming, you could easily navigate the page and read the content.

Now every major platform supports great Web page rendering, but the speed at which the device does this is far slower than how a desktop browser does it. A survey by Compuware shows that fully 71% of users expect sites to load as fast on their phones as they do on their desktops.

That just isn't realistic. As capable as phones are, they are still far less powerful than a desktop machine. When loading a Web page, a PC can make use of a separate video chip with lots of RAM, multiple processor cores with a hefty onboard cache for each one, tons of system RAM to cache files, and a relatively fast hard drive to write the data. While a phone may have some of those features, they have only a fraction of the power of their desktop counterparts, constrained both by size and power-consumption goals.

When it comes to loading pages, users are apparently very impatient--71% only wait five seconds or less for a page to load, and 60% only stick around for three seconds.

All of this culminates in a disappointing experience, and it's something a company that is trying to capture mobile surfers should be aware of. Yes, chances are today's mobile browsers will correctly render your page, but unless it loads fast, mobile users won't spend much time at your site. This isn't about bandwidth, because in many instances, 3G or Wi-Fi have similar performance. It is about rendering power, and the more code you have in your page, the worse the performance is likely to be for the user.

You can see these and other related stats in this related infographic.