Is a 32-bit build faster than a 64-bit build

[Stefan Behnel]

Raymond Hettinger, 12.11.2010 22:24:
> Has anyone here benchmarked a 32-bit Python versus a 64-bit Python for
> Django or some other webserver?
>
> My hypotheses is that for apps not needing the 64-bit address space,
> the 32-bit version has better memory utilization and hence better
> cache performance.

OTOH, x86_64 has more registers and allows faster compiler flags for 
default installations (e.g. there is no x86_64 processor without MMX and 
SSE). So, if you don't compile your software yourself (including OS kernel 
and libraries, e.g. OpenSSL), it will likely run faster on 64bits simply 
due to the better compiler optimisations.

There are good reasons for both being able to run faster depending on the 
specific code, so benchmarking is basically all you can do.

Stefan