[arch-general] аrch x86_64 and i686 performance comparison

[Smith Dhumbumroong]

On Wed, 11 Nov 2009 09:11:02 -0700
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
> 

Like most people have already said, benchmarking using virtual machine
is not a good idea as the results will most likely _not_ reflect the
actual performance.

Better to install both Arch 32-bit and 64-bit on the same machine (dual
boot) and run the tests.

I've used 32-bit Arch Linux in the past before switching to 64-bit and
from my personal experience certain operations, such as video/music
encoding, is a _lot_ faster on 64-bit. I didn't timed it back then,
but it was almost twice faster than on 32-bit.

Regards,

Smith