Internet Explorer 9

There's little change in the look and feel of IE9 from the beta: tabs have changed shape, and there's the option to move them to another row, but that's about all

It's a year since Microsoft delivered the first Platform Preview for its re-engineered Internet Explorer 9. Throwing away much of its legacy, IE9 has been designed to be a fast, relatively lightweight, standards-compliant browser. It's also been one of Microsoft's most open development processes yet, with eight developer-targeted platform previews, a beta and a release candidate, 17,000 bug and feature requests, and over 40 million downloads.

Microsoft's data-driven development process means there's little change between the release candidate and the final code, with the browser keeping the same minimalist user experience and building on the GPU acceleration capabilities of modern PCs. There aren't any new HTML5 or CSS3 features in the release version of IE9, with Microsoft instead focusing on the end-user experience, while tweaking browser performance, page rendering and tuning its multicore Chakra JavaScript engine.

Keeping yourself private online is a lot easier with IE9's tracking protection tools: turn them on from the Safety menu, where you can also enable ActiveX filtering

The most obvious changes are to IE9's consumer protection features, adding support for the proposed 'Do-Not-Track' header. When a user chooses to use IE9's tracking protection lists, IE9 will automatically add the header to browser requests — although it's up to web sites to actually implement code that interprets and uses the header. The RC used tracking protection to block cookies, but tracking protection lists now also apply to ActiveX controls, blocking them from loading from sites on the lists. Although it doesn't prevent controls from bypassing tracking protection by downloading content from blocked sites directly, Microsoft has added APIs to IE9 that let ActiveX controls subscribe to tracking protection lists, so that they can use them to give the same privacy features. We don't expect these features to roll out overnight — it'll take time for, for example, for Adobe to add them to Flash.

You can use the tracking protection tools in IE9 to build your own list based on the site and services you visit — and the advertising and tracking services they use: you can choose to block the most commonly used services, so you're no longer followed from site to site

We're pleased to see Microsoft thinking of user privacy, and mixing this latest version of IE9's tracking protection tools with its ActiveX filtering feature actually gives IE9 a respectable ad-blocking capability we'd like to see built into other browsers. It also avoids the overhead of installing an ad blocker, as you don't need a second application interpreting page HTML and content.

At a much lower level there are changes to the way IE9 works with lower-end GPUs, such as those used in netbooks. In the past these weren't able to take advantage of the browser's GPU acceleration, often due to the way they use shared memory. As browsers are memory-intensive applications this could be a problem, leading to significant performance issues. Microsoft has now optimised memory usage, speeding up performance with these GPUs — making some operations up to two times faster.

Site pinning makes web sites act more like applications, with IE9 taking its colouring from the site, and with jumplists in the toolbar to quickly take you to where you need to be

There are also changes to the way Microsoft supports creating pinned sites — browser windows that are added to the Windows task bar and treated as applications in their own right. Pinned sites have proven very successful (Microsoft quotes Livestrong as seeing users who pinned the site spending 53 percent more time using the site, and being 40 percent more likely to return), so it's making them easier to create. The IE9 RC allowed developers to attach site pinning functionality to a draggable image on a page, something the final release extends to allowing multiple sites to be pinned from a single action.

Performance
We ran IE9 through a series of web benchmarks to see how it performed, comparing it with the latest releases of Chrome, Firefox and Safari (unless otherwise stated, larger numbers are better).

	Internet Explorer 9	Chrome 11 (dev)	Safari 5	Firefox 4 (RC)
HTML5test (out of 400)	130 (+5)	293 (+11)	228 (+7)	255 (+9)
ACID3 (percent)	95	100	100	97
CSS Selectors (out of 574)	574	558	574	574
Peacekeeper	4373	7273	3838	3026
Kraken (smaller is better)	18734.7	10059.6	20924.8	8108.9
SunSpider (ms, smaller is better)	289.9	394.7	453.2	336.9
VP8	1967	6556	1985	2600
JSBenchmark (smaller is better)	370	615	397	465

There's a lot of difference between the many browser benchmarks. Although the focus is generally on JavaScript interactions with the browser, the most balanced is probably Futuremark's Peacekeeper. Coming from a company that specialises in developing benchmarks, it exercises a wider set of browser capabilities than benchmarks derived from specific browser test suites. There are also questions over the validity of some popular tests: some, like the ACID3 and HTML5test, look for browser support for tags and elements that have yet to be ratified by the W3C. As such they're perhaps better thought of as self-monitoring wish lists rather than true benchmarks.

We used the Peacekeeper benchmark to test IE9, on a PC with a quad-core processor, 2GB of RAM and an NVIDIA GPU, comparing it with the latest releases of Firefox, Chrome and Safari

Peacekeeper ranks IE9 second among the four main browsers, coming in behind Chrome and ahead of Firefox 4 and Safari 5. Its results mirror real-world experience on a range of web sites, and leave us happy to recommend IE9 as a considerable upgrade to earlier versions of Internet Explorer. What's perhaps most interesting about the benchmarking exercise is just how fast all the main browsers are, with very small differences between them. Your online performance is no longer a function of your browser — it's now directly linked to your PC's performance and the code on the site you're visiting. Web application development — especially JavaScript development — has to be treated the same as any other application-development process, using tools like IE9's improved debugging and profiling features to ensure that code is running as efficiently as possible.

Microsoft is using the launch of IE9 to encourage businesses to give up using IE6. It's certainly something Microsoft can show as a commitment to the future of the web, but we're not sure if it will significantly change IE6 usage. With IE9 only available to Vista and Windows 7 users, it's not going to be an upgrade for any of those Windows XP desktops still running IE6. If there's a single thing that's going to persuade businesses to upgrade those PCs it's the arrival of Windows 7 SP1, which should drive another PC upgrade cycle.

Conclusion
This is Microsoft's best browser — so far. That's not damning with faint praise, as IE9 has put Microsoft back in the game, making it a recommended install for any supported Windows PC. It's offering technical innovation with GPU-powered rendering, and standards support with an (admittedly numbers-driven) commitment to HTML5 — and in double-quick time too, pushing the rest of the browser industry to follow.

Microsoft is no longer seen as an HTML laggard holding back the web, and is now firmly part of the 'modern browser' school. We hope to hear more of Microsoft's plans for its browser in a month or so at the MIX conference: it's a future we hope will be one of rapid and regular updates — if only to keep the rest of the browser industry on its toes.