interesting Athlon/P4 discussion from FreeBSD-Q-l

[Arthur H. Edwards,1,505-853-6042,505-256-0834]

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