Re: cpu comparison

On Mon, Jul 18, 2011 at 11:56:40PM +0200, Tomas Vondra wrote:
> Dne 18.7.2011 22:11, ktm(at)rice(dot)edu napsal(a):
> >> > In my testing I have a 32bit CentOS on the x3450, but a 64bit CentOS
> >> > on the E5335. Can this make such a bit difference or should the
> >> > perform fairly close to the same speed? Both servers have 8GB of
> >> > RAM, and the database I tested with is only 3.7GB.
> >> >
> >> > I'm a bit surprised as the x3450 has DDR3, while the E5335 has DDR2,
> >> > and of course because of the cycle speed difference alone I would
> >> > think the X3450 should beat the E5335.
> >> >
> > Yes, you have basically shown that running two different tests give
> > different results -- or that an apple is not an orange. You need to
> > only vary 1 variable at a time for it to mean anything.
>
> He just run the same test on two different machines - I'm not sure
> what's wrong with it? Sure, it would be nice to compare 32bit to 32bit,
> but the OP probably can't do that and wonders if this is the cause. Why
> is that comparing apples and oranges?
>
It is only that 32 vs. 64 bit, compiler and other things can easily make
a factor of 2 change in the results. So it is not telling you much about
the processor differences, neccessarily.

Regards,
Ken