Thanks for sharing.
Here is what google has to say about the 64bit version
Google claims the 64-bit builds come with a number of improvements:
- Speed: 64-bit allows us to take advantage of the latest processor and compiler optimizations, a more modern instruction set, and a calling convention that allows more function parameters to be passed quickly by registers. As a result, speed is improved, especially in graphics and multimedia content, where we see an average 25% improvement in performance.
- Security: With Chrome able to take advantage of the latest OS features such as High Entropy ASLR on Windows 8, security is improved on 64-bit platforms as well. Those extra bits also help us better defend against exploitation techniques such as JIT spraying, and improve the effectiveness of our existing security defense features like heap partitioning.
- Stability: Finally, we've observed a marked increase in stability for 64-bit Chrome over 32-bit Chrome. In particular, crash rates for the the renderer process (i.e. web content process) are almost half that of 32-bit Chrome.