Ubuntu 11.04: i686 vs. i686 PAE vs. x86_64
Phoronix: Ubuntu 11.04: i686 vs. i686 PAE vs. x86_64
At the end of 2009 I published benchmarks comparing Ubuntu's 32-bit, 32-bit PAE, and 64-bit Linux kernels. Those tests were carried out to show the performance impact of using 32-bit with PAE (Physical Address Extension) support, which on the plus side allows up to 64GB of system memory to be addressable from 32-bit machines, but is still significantly slower than a 64-bit kernel and user-space. In this article the tests have been carried out on modern hardware and with the latest Ubuntu 11.04 packages to see how the three kernel variants are performing in 2011.
Why Canonical is not promoting x86_64?
First of all, some of the main and most popular third party software don't have 64bit support. Skype, Adobe Reader, Adobe Flash Player among other ones.
In particular the latter is known to be important (if not mandatory) for web contents.
And they don't want to have users getting bad web experience from Ubuntu.
Second, in a number of places you can read that a 64bit desktop PC is not that faster than a 32bit conterpart. If that's not a urban legend, it's at least a common belief none has cleared so far. So let's stay on the mainstream.
Third, yours (Phoronix') is among the very few comparisons I've seen so far between 32bit and 64bit system. And most of the users and decision makers can struggle a lot to understand the real meaning of it. Companies rarely aim products and services to "geeks", any way.
Fourth. People coming from the Microsoft world (that's not me) "know" that there "can be problems" in getting 64bit working drivers and software if they choose a 64bit OS. Yes, they can still run 32bit stuff in a 64bit environemnt, but then, why should they?
So proposing users the same choice they'd hear from the "normal" world brings more trust. That's money.
In the end, all that could be just ignorance in it's broader meaning. But this is the "real world" (tm) where a PC sells better than an Amiga or an Archimedes. Sigh!