Chromium's Introduction of 64-Bit Windows Support

This article provides a timeline and overview of when the Chromium web browser first introduced native support for 64-bit Windows operating systems. It details the specific release dates in 2014, the milestone version numbers, the reasons behind the transition, and the performance and security benefits that native 64-bit architecture brought to Windows users.

The Chromium project first introduced usable, native 64-bit support for the Windows operating system in mid-2014 with the development of Chromium 37. Prior to this milestone, Windows users on 64-bit machines were forced to run the 32-bit version of the browser through Microsoft's WOW64 (Windows 32-bit on Windows 64-bit) compatibility layer.

The rollout of 64-bit Windows support occurred in distinct phases throughout 2014:

• May 2014: The first functional 64-bit Windows builds began appearing in the open-source Chromium continuous build trunks for developers to test.
• June 3, 2014: Official experimental builds based on Chromium 37 were released to the public via the Canary and Dev channels, specifically targeting Windows 7 and Windows 8.
• August 26, 2014: The 64-bit architecture reached full maturity and was pushed to the stable channel with the final release of version 37.

While Chromium had supported 64-bit Linux operating systems since 2009, bringing the same support to Windows took significantly longer. Developers faced several hurdles, including the need to rewrite parts of the Windows-specific sandbox security model, issues with pointer sizes in the codebase, and the challenge of maintaining compatibility with older 32-bit plugins and extensions.

Once implemented, native 64-bit support delivered three immediate improvements to the browser on Windows:

Enhanced Performance The 64-bit architecture allowed Chromium to utilize more CPU registers and newer instruction sets on modern processors. This resulted in an immediate 25% speed improvement in graphics and multimedia benchmarks, particularly when decoding high-definition video.

Stronger Security Running natively on 64-bit Windows allowed the browser to take full advantage of newer operating system security features, such as High Entropy Address Space Layout Randomization (ASLR). By vastly expanding the memory address space, it became exponentially more difficult for malicious code to predict where specific browser processes were located in the system's memory.

Greater Stability The 32-bit version of the browser was limited to accessing a maximum of 4 gigabytes of RAM, which frequently led to out-of-memory crashes during heavy multitasking. The 64-bit version removed this ceiling, cutting the crash rate of rendering engines by nearly half compared to the 32-bit builds.