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Old February 3rd 04, 04:47 AM
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On Mon, 02 Feb 2004 12:13:51 -0800, Paul Spitalny
wrote:


Hi Ancra,
Well, I asked the software vendor (the software that I run to do
simulation work with) about the mathematics in their program and this is
what they said:

Q: Does the code use mostly floating point math operations. If so, then:
What _kind_ of floating point math is it?
Is it compiled to old fashioned '387 operations?

A: Yes. We compile generic version which must be supported by most
number existing x86 processors as possible. As result we don't optimize
Sthe code for particular x86 instruction set extension.

Q: Or is it autovectorized/optimized for SSE2?
A: No.

Q: Is it double precision or single?
A: Double as in original Berkeley Spice 3.

Q: Does it contain division, how much?
A: It's hard to tell. It's depend on what you want to simulate with
SmartSpice.

Q: Is there a lot of conditional instructions, branches?
A: Sure.

Q: Is the code (for windows) compiled with Intels auto vectorizing
optimizing
compiler?
A: No.

That being the case I wonder how to proceed. I can halp but think that
the newest "extreme" pentium (now up to 3.4Ghz clock and 800MHz FSB) has
got to be significantly faster than my older 2.5GHz pentium 4 (with
RAMBUS memory). The "extreme" processor has 1Meg of L2 cache and you
would think that'd help too.

Or, do you feel like the AMD chips might be better since they are known
for better performance at floating point? You see, the guys I get my
software from, as they mention above, don't compile for specific
processors or to optimixe performance.

By the way, thank you for your response to my posting!!


With those answers, it might be worthwhile to try AMD!

Is it just me, or wouldn't it be a simple matter for you to check?
Just borrow an AthlonXP machine and try the software on it. You should
get some definite indication.

The P4 has weaknesses, and some of those are basically everything you
listed... Whatever article you've read, I can almost guarantee you
every single synthetic benchmark is virtually 100% SSE2.

While I can't predict the outcome with any certainty, I think you
should definitely try to see what an AMD cpu makes of it.
So I wouldn't look to either P4, Extreme Edition or Prescott for a
solution. Because my perception is that the Intel architecture might
not cut it.
Sure, it would be an improvement, but as you might gather I doubt it
will be "fastest". Also, if a P4EE is going to run continuously on
100% for hours, you need some good cooling solution, or it will just
throttle. It's also going to cost an awful lot of money, for very
little more performance than a vanilla P4C.
With that kind of money for a PC, I'd start to go crazy and drool over
plans for a Prometheus case, DDR533 and CPU frozen to -40degC and
overclocked 30-40%.

If AMD checks out, a machine that would look attractive to me are the
coming socket 939 Athlon64_3400+ or 3700+.
Dual channel Athlon64s looks like the perfect science/math
PC-workstation to me.

Spice sounds vaguely familiar. Isn't that analog electric circuitry?

ancra