[arch-general] аrch x86_64 and i686 performance comparison

[Sergey Manucharian]

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