Subject: Xeon Summary

From: Gary Kedziora <[email-masked]>
Date: Fri, 13 Aug 1999 12:13:28 -0500 (CDT)

I must leave on vacation this weekend, so I will summarize now
what little information I have Xeon processors compared directly
with Pentium II/III.  I recieved only two substantive replies.

ORIGINAL QUESTION:
Has anyone seen a comparison of the performance of a Xeon processor
with a straight Pentium II or III at the same (or nearly the same)
clock speed?  I'm interested in performance comparisons using
the usual chemistry applications, good cache-optimized code--
not implying there is no good cache-optimized chemistry code--or 
any other benchmark.

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REPLY 1 (from [email-masked]):

Hi,
I was testing a normal pII450 against a pII450 xeon with 1024 kb cache.
The application was Gaussian94 compiled with the f2c-gcc combination, the
tests jobs were geom. optimizations and freq. calculations on 10-atom
molecules with 70-250 basis functions and the results were disappointing:
the xeon was only about 5 % faster, despite the bigger and faster cache.

                dino   
                [email-masked]
-------------------------------------------------------------------------------
REPLY 2 (from [email-masked]):

The German magazine c't has published SPEC values from a comprehensive
comparison of P-III/600, Athlon-600 and some Xeon-450 (?) based machines.

Basically the result is, AMD wins every category (x86-only, of course :-),
I can look up the numbers or fax you a copy of the article if you
want. (Its German, numbers are understandable, though, I guess)

-- Jochen
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MY FINDINGS/THOUGHTS:

I found a review on the web with direct comparisons between regular 
PIIs and PIIIs and corresponding Xeon processors.  This used benchmarks
I'm not familiar with and may not be very relavent to scientific 
programs.  The results are that Xeon helps by a few percent.
The URL for the review is 
http://www.review-zone.com/hardware/processors/intel_pentium-iii_xeon_500/Page1.
html

One must have to work hard to squeeze out significant (or more likely
marginal) improvement over the PIII. Is it worth the money to get
a Xeon?  Probably not.  

I spent some time hunting around Intel's web pages looking for 
a direct comparison and found nothing obvious. I think that tells you
something.

AMD's website says "a 550MHz AMD Athlon processor has more than 35
percent higher performance than either a 550MHz Pentium III or a Pentium III
Xeon on the SPECfp_base95 benchmark" (http://www.amd.com/news/prodpr/9988.html).
AMD now has a 650 MHz version with a 200 MHz bus.  That sounds good.

__
Gary Kedziora // Department of Chemistry // Northwestern University 
email: [email-masked]//ph: (847)467-4857//fax: (847)491-7713