interesting Athlon/P4 discussion from FreeBSD-Q-l

[Michael T. Prinkey]

I have been watching the Athlon/P4 issue from a safe distance for the
past few months, but at the request of a client, I finally bought Athlon
and P4 test systems.  The target application is a commercial CFD code. 
When I did the benchmarking, I was astonished.  The 1.5-GHz P4/RDRAM
system simply ran rings around everything else, including a fairly new
Compaq ES40.  Numbers look something like this:

ES40, 500 MHz           1.70 iterations per minute
Athlon, 1.33 GHz/DDR    1.85
P3 933 MHz/Serverworks  1.10
P4 1.5 GHz/i850/RDRAM   3.00

This was genuinely unexpected.  Needless to say, I have a new found
respect for the P4 and RDRAM, at least for this application.  And as has
been pointed out, we are now under $2000 for a rackmount 1.7-GHz P4 node
with 1 GB RDRAM.

Mike Prinkey
Aeolus Research, Inc.

"Arthur H. Edwards,1,505-853-6042,505-256-0834" wrote:
> 
> Mark Hahn wrote:
> 
> >> Cant vouch for correctness, but seems to have some explanations/info that
> >> werent mentioned here. Feel free to rebut the content of course.
> >
> >
> > the P4 has an awesome combination of hardware prefetcher,
> > fast FSB, and dram that keeps up with it.  for code that
> > needs bandwidth, this is very attractive.  and it's dramatically
> > faster than anything else in the ia32 world: 1.6 GB/s versus
> > at most around .8 GB/s for even PC2100 DDR systems (at least
> > so far - I'm hopeful that DDR can manage around 1.2 GB/s when
> > tuned, and if the next-gen Athlon contains hardware prefetch.)
> >
> > but it's also true that most code, even a lot of computational code,
> > is not primarily dram-bandwidth-bound.  the P4 is not exceptional
> > when running real code in-cache; this is why on most benchmarks
> > other than Stream, recent Athlons beat P4's quite handily.
> >
> > and that's why AMD is having such an awsome time in the market now,
> > and why Intel is cutting prices so dramatically on the P4.
> >
> > regards, mark hahn.
> >
> >
> > _______________________________________________
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> >
> >
> >
> Is anyone doing anectdotal benchmarks with real applications? We are
> doing DFT calculations using a local basis code that is highly optimized
> on serial machines. I am working on pentium III's, athlon's, and alpha
> machines. I find that my 600 MHz athlon actually beats a 933 MHz Pentium
> III. Also, both of these PC platforms are competitive with the alpha chips.
> 
> I'm much more interested in benchmarks on, say, Gaussian 98, GAMESS, and
> other codes. Any Athlon/P4 comparisons would be very interesting.
> 
> Art Edwards
> 
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