Re: [Ngspice-users] Performance problems with Athlon 64 X2?

[John B. <jbr...@gm...>]

If your gcc flags are not set to take advantage of your specific
architecture, you may be leaving performance on the table.

Actually, the transition from executing 32-bit to executing 64-bit code is
known in some memory intensive applications to cause a reduction in
performance due to the increased size of memory addresses and payloads (all
else being equal).  At least this was a subject another student at my
University was pursuing casually and had shared with me a few months ago.

However, I have never compiled for or simulated on an AMD machine.  I
haven't run extensive simulations yet to compare the run times of 1 64-bit
Intel core from a quad-core machine to 1 32-bit P4 thread. Or the comparison
of 4-Cores to 2-Threads.

I would also appreciate anyone's thoughts on this topic.

On 5/10/07, Bill Richards <ric...@tb...> wrote:
>
> Hi-
> I recently upgraded my simulation system from an old XP 1600+ box to an
> Athlon 64 X2 3800+.  I grabbed the x86_64 ngspice package via yum, and
> ran some test cases.  To my surprise, mt test cases ran SLOWER on my new
> Athlon 64 box!!  Being somewhat paranoid of binary RPMs, I downloaded
> the sources and necessary libraries and made it all from scratch.  Ran
> the test cases, and again, the ngspice code on my new box yielded
> exactly the same results as my old box, only over 2X slower!!!  Has
> anyone encountered this kind of behavior with ngspice on an Athlon 64 box?
> I don't have any other benchmarks to compare performance of this machine
> against my now-defunct old machine.  Any help or suggestions would be
> appreciated!
> Thanks,
> -bill-
>
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