Today’s Chrome Beta channel release includes a ton of new primitives and APIs to simplify development and give developers more control over their web applications. Unless otherwise noted, changes described below apply to Chrome for Android, Windows, Mac, Linux, and Chrome OS.

New HTML element: <picture>

This release adds support for the new <picture> element thanks to the hard work of community contributor Yoav Weiss, who was able to dedicate his time to implementing this feature in multiple rendering engines because of a successful crowdfunding campaign that raised 50% more than its funding goal.

The <picture> element takes the concept of responsive design, previously solved by sending duplicate resources to the client, and bakes an elegant solution right into the web platform. It allows developers to list multiple versions of images that may be appropriate for the browser to display based on screen size, pixel density, or other factors.

On the heels of Tuesday’s release of 64-bit Chrome for Windows, all Mac Chrome users on the beta channel will be updated to a new 64-bit version of Chrome 38. Previously, Chrome was a 32-bit app on Macs. While doubling the number of bits won’t make things twice as good, it does allow us to make a number of speed and security improvements.

64-bit Chrome has become faster as a result of having access to a superior instruction set, more registers, and a more efficient function calling convention. Improved opportunities for ASLR enhance this version’s security. Another major benefit of this change comes from the fact that most programs on a modern Mac are already 64-bit apps. In cases where Chrome was the last remaining 32-bit app, there were launch-time and memory-footprint penalties as 32-bit copies of all of the system libraries needed to be loaded to support Chrome. Now that Chrome’s a 64-bit app too, we expect you’ll find that it launches more quickly and that overall system memory use decreases.

Because of this change, Chrome for Mac will no longer support 32-bit NPAPI plugins, although their 64-bit counterparts are supported. Users shouldn’t notice any changes, because most major plugins are available in both 32-bit and 64-bit form, and many major websites have been switching from NPAPI towards more modern HTML5 APIs. This is also a good time to remind everyone that NPAPI support will be removed from Chrome later this year.

Nearly every Mac user has a computer capable of running this 64-bit version, so we’re automatically updating all Mac Chrome beta channel users. Those few users with first-generation Intel Macs will miss out on the fun, but as we bid them farewell, we’ll remind them that they’ll still be able to run the latest version on the stable channel, Chrome 37.

You can check to see if the Chrome you’re running is a 64-bit version by checking Chrome’s About page (chrome://help) and looking next to the version number. If it says “64-bit” there, that’s a sure sign that you’re running one of these new builds. We hope that this is the only visible difference that you’ll find between the old 32-bit and new 64-bit versions, but in case you find anything amiss during the beta period, please let us know.

Posted by Mark Mentovai, Software Engineer and Register Doubler

64-bit Chrome offers many benefits for speed, stability and security. Our measurements have shown that the native 64-bit version of Chrome has improved speed on many of our graphics and media benchmarks. For example, the VP9 codec that’s used in High Definition YouTube videos shows a 15% improvement in decoding performance. Stability measurements from people opted into our Canary, Dev and Beta 64-bit channels confirm that 64-bit rendering engines are almost twice as stable as 32-bit engines when handling typical web content. Finally, on 64-bit, our defense in depth security mitigations such as Partition Alloc are able to far more effectively defend against vulnerabilities that rely on controlling the memory layout of objects.

At this point 64-bit will remain opt-in, so to take advantage of the improvements click on the new “Windows 64-bit” link on the Chrome download page. Currently, the only significant known issue is the lack of 32-bit NPAPI plugin support. The 32-bit channel will remain fully supported for the foreseeable future and we will continue to support 32-bit plugins until NPAPI is removed from Chrome.

We encourage you to give 64-bit Chrome a try. We’re looking forward to hearing your feedback so we can continue to make Chrome the fastest, most secure and stable browser.

Posted by Will Harris, Software Engineer and Embiggener of Bits