News

Microsoft Claims IE 11 Speeded Up by Content-Fetching Technologies

• By Kurt Mackie
• 12/05/2013

Microsoft explained some speed improvements made in its latest Internet Explorer 11 browser, attributing them to resource optimization and caching technologies.

IE 11 was released in June for Windows 8.1, and Microsoft subsequently released the new browser for Windows 7 in November, claiming JavaScript processing speed improvement over competing browsers, based on Webkit SunSpider tests. Microsoft also has noted some speed improvements based on IE 11's JPEG processing capability, which taps a system's graphics processing unit.

This week, Microsoft announced speed improvements in IE 11 based on "page prediction, preload and prefetch" technologies, as well as IE 11's support for the SPDY 3 protocol. However, not all of the improvements apply because the SPDY protocol isn't supported by IE 11 on Windows 7.

SPDY 3 is part of the next iteration of HTTP, called "HTTP 2.0," that's being developed by the Internet Engineering Task Force. Microsoft describes SPDY 3 as an "experimental protocol that can speed up page load time by combining multiple requests into a single network connection." IE 11 on Windows 8.1 automatically uses SPDY 3, and while not all Web sites support that protocol, Facebook and Twitter currently use it, according to Microsoft.

Prediction, Preloading and Prefetch
Microsoft's "page prediction" technology in IE 11 automatically loads a page in advance, based on user's browsing patterns, to speed page access. The process is partly based on the Web data-mining capabilities of Microsoft's Bing search engine, according to Microsoft.

Developers also can speed up the browsing experience in IE 11 on their sites by "preloading" pages. The preloading process works by adding the <link rel="prerender"> tag to Web page code. That tag is currently being standardized by the Worldwide Web Consortium, according to Microsoft. Preloading does use some system resources to work, though.

The "prefetch" technology in IE 11 is another way to speed up the browsing process by accessing scripts and stylesheets on a Web page in advance. Developers use the <link rel="prefetch"> tag in their code to specify what will get fetched. Microsoft claims that prefetch "uses almost no memory or CPU resources," even while it can reduce page loading times by around 66 percent.

Resource Use
These approaches in IE 11 amount to better overall resource use, Microsoft claims. They are especially useful for mobile devices, which have limited battery capacities.

"On your portable devices that have limited resources, the IE 11 approach can end up making a big difference to battery life and system performance," Microsoft's announcement claimed. 

For the most part, Web sites can't drain system resources when using these technologies because IE 11 will limit "the number of preload and prefetch operations from each Web page." IE 11 also does not preload or prefetch content on metered networks, according to Microsoft.

However, those who don't want the preload and prefetch capabilities in IE 11 can turn them off. It's done by unchecking a setting, called "Load sites and content in the background," which is located in the Advanced tab under the browser's Internet Options selection.

Microsoft also claims that IE 11 is the first browser to support the "lazyload" tag descriptor, which can be used by developers to lower the loading priorities for a particular aspect of a page, such as deprioritizing the loading a particular JPEG image. The example Microsoft gives is <img src="image.jpg" lazyload />.  Microsoft is urging the Worldwide Web Consortium to get behind lazyload as recommendation.