[arch-general] аrch x86_64 and i686 performance comparison

[Evangelos Foutras]

On Wed, Nov 11, 2009 at 6:11 PM, Sergey Manucharian <sergeym at rmico.com> wrote:
> Hi folks,
>
> The similar question most probably has been discussed many times, but I
> really cannot find a clear answer. There are some obvious thinks like
> 64-bit addressing, but how about math calculations performance?
>
> I've set up two identical virtual machines in vbox - one with Arch
> x86_64 and another with Arch i686. I ran mencoder in both over the same
> video and got the following figures:
>
>  x86_64: 43 sec
>  i686:   34 sec
>
> which make x86_64 not so impressive ;)
>
> Some time ago I read an article at AMD web site, they suggested using
> their math libs for writing programs instead of standard ones. In such
> a case a program with complex math involved can performs much better
> (personally I haven't tried).
>
> I'm just curious about other people's opinions on this subject.
>
> Cheers,
> Sergey

I don't think you should be benchmarking using virtual machines. The
overhead imposed by virtualbox is not negligible and can differ
greatly between the two architectures.

Maybe running off of Live CDs would give more accurate results.