amd64 slower than i386 on identical AMD 64 system?

Alexander Konovalenko kono at
Tue Mar 14 16:10:03 UTC 2006

On Tuesday 14 March 2006 12:49, ray at wrote:
> +2 cents mode on... :)
what do you mean?

> I'm just coming in on the tail end of the message (missed the previous
> stuff). I recently did some benchmarks between AMD64 and i386 (version 5.4)
> on the same hardware.  I initially saw that the i386 ran faster also. 
> However, after searching a bit further, I discovered that I had made an
> error: the i386 kernel has the SMP stuff compiled into the generic kernel
> by default, while the AMD64 (at least on 5.4) does not.  It has a separate
> kernel file called SMP (as I recall), which adds the SMP line and then does
> an include for the rest of the generic kernel config file (or something to
> that effect).
> Anyway, if you are testing back and forth, it's easy to forget that and end
> up accidently testing an i386 with SMP against an AMD64 without SMP.
> Like I say, I'm coming in on the tail end of the thread, so I might be off
> base, but it might be something worth double checking - just to be 100%
> sure.
> :-)
> Ray

I am just trying to understand, the conclusion is that all people who got i386 
benchmark better than amd64 one, on the same X2 hardware, were running not 
SMP kernel on amd64 and never bothered them self to build and use a proper 
kernel for their platform? Naively I thought that problem is much 
serious... :-P


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