Users have wanted a 64bit Chrome browser for quite some time and with Firefox, Opera, and Internet Explorer allhaving 64bit versions (though Firefox does not officially support their 64bit builds) it’s a bit surprising that Chrome hasn’t released one.
The Chromium bug for 64bit support has gotten some activity recently though. We can hope this continues.
The benefits of a 64bit browser are numerous but also variable – 64bit is not magic, you don’t get it to compile for 64bit and suddenly have a super speedy browser, you have to optimize for 64bit and really make sure you take full advantage of the potential that comes along with it.
Some of that potential is directly related to security.
When most people think of 64bit they think of being able to access more RAM. The reason 64bit can access more RAM is because it can address 2^64 bits of data, whereas 32bit can only access 2^32 bits of data. This also means that it can access files of a size up to 2^64bits and that it has an address space of up to 2^64bits (although it’s not that large).
A larger address space will significantly improve ASLR, which relies on randomizing areas of address space. If you want to find random values between 1 and 10, there are only so many times you have to guess no matter how strong the random dumber generator is – make that between 1 and 1,000,000 and things get much harder to guess.
On Windows 8 64bit processes can opt into High Entropy ASLR, which improves the randomization of address space further, by increasing the randomness of memory allocations.
So 64bit Chrome will make things more difficult for attackers, especially on Windows 8.
In terms of performance there may or may not be significant improvements. 64bit comes with a downside, pointers are twice the size, and apparently for a browser that could end up being an issue due to how data is structured. Mozilla was working on 64bit Firefox but dropped the project because the benefits were not outweighing the development costs.
Star the Chromium bug if you’d like to see work on 64bit Chrome and Chromium for Windows continue.