Between the Internet Explorer 9 Beta and Internet Explorer 9 RC releases over 2,000 changes have been made to improve browser performance for real customer scenarios. Internet Explorer 9 RC starts faster, loads webpages faster, and allows you to interact with webpages faster than ever before.

Chakra, the new JavaScript engine for Internet Explorer 9 RC, has continued to be tuned for the common patterns found across real-world websites. Chakra uses advanced techniques traditionally only found in desktop optimizing compilers. A byproduct of improving the performance of Chakra for real-world scenarios is that Internet Explorer 9 RC is now the fastest JavaScript engine on the WebKit SunSpider Benchmark.

Internet Explorer 9 RC now dynamically decides when to use GPU based rendering and when to use software based rendering based on the customer’s GPU and installed graphics driver, which ensure the fastest possible experience for all customers by default.

By leveraging the GPU for graphical computation, Internet Explorer 9 RC saves significant power and leads the industry in power consumption by allowing the CPU to sleep for longer durations. Internet Explorer 9 RC is also the only browser on the Windows platform that integrates with the Windows Power Options and respects customers’ power settings to conserve power and maximize battery life.

The new features in the Internet Explorer 9 Release Candidate (RC) continue to refine and improve the usability of the browser.  Menu bar toggle allows you to permanently enable the menu bar with just a few clicks.

Internet Explorer 9 RC also gives you even more space to let your sites shine by reducing the frame pixels by five over the beta release to see more of your favorite site’s content.

With the RC Build, we continue to listen to customers and have implemented the ability to place tabs on a separate row from the address bar providing you more space for all your tabs.

We’ve also improved the visibility of the active tab and enabled you to close background tabs without selecting the tab by exposing the close button on hover.  A single tab can also be closed using the close button on the tab, which behaves the same as the frame close button.

You will now be able to pin multiple home pages in a single pinned site with Internet Explorer 9 RC and open several webpages simultaneously.  This will both reduce the clutter on the task bar and make browsing to your favorite sites available with a single click. Additionally, it’s now possible to pin sites to your taskbar wherever it’s positioned and for developers to implement drag-to-pin support right on their pages.

Some content on websites can be used to track your activity as you browse the web. Tracking Protection allows you to limit the browser's communication with certain websites—determined by a Tracking Protection List—to help keep your information private. Anyone can create Tracking Protection Lists, and there should be many to choose from in the near future.

ActiveX is a technology that allows web developers to create interactive content on their sites, but it can also pose a security risk. Internet Explorer 9 RC allows you to block ActiveX controls for all sites, and then turn them back on for only the sites that you trust with the new ActiveX Filtering option.

InPrivate browsing is now supported on pinned sites giving you more choice and increased privacy across all your browsing experiences. When you pin a site with InPrivate browsing enabled, the next time you launch the pinned site, the browsing session is automatically enabled as InPrivate.

Internet Explorer 9 RC adds support for the CSS3 2D Transforms module, which enables elements that are rendered by CSS to be transformed in two dimensional space. 

Internet Explorer 9 RC improves support for several HTML5 semantic tags where a semantic element is defined as one whose tag name describes its content, but which does not have any special behaviors.  Elements now inherit from HTMLElement and by default the elements are now styled as specified in the HTML5 specification.

With support for geolocation, Internet Explorer 9 RC enables a web application to access the current geographical location of the PC running Internet Explorer, as specified in the Geolocation API specification.  The webpage can then tailor the user experience according to location.

Internet Explorer 9 RC supports playback of H.264-encoded video using the HTML5 video tag and now WebM video as well when a VP8 codec is installed on Windows.