Subject: CCL: Re: Pentium vs. PowerPC speeds for quantum chemistry?

From: [email-masked] (Joerg Hill)
Date: Wed, 27 Jul 1994 16:39:00 -0700

> I'm trying to compare the capability of a 32 MB/2GB pentium system that
> costs about $5600 to a PowerPC based IBM RS/6000 that costs more than
> twice as much for the same configuration.  Given that similar codes are
> now available for both, does anyone have *real* tests of computational
> chemistry codes (speed, ease of use).  Will the PowerPC as implemented
> by IBM really provide twice the performance (both are 66 MHz).

I think it should first be clarified that the PowerPC and the IBM RS/6000 CPU
are two similiar (binary compatible), but nevertheless different things. The
IBM RS/6000 CPU is the first implementation of IBM's so-called POWER
architecture (Performance Optimization With Enhanced RISC). It consists of
five chips. The PowerPC (chip) is a single chip microprocessor which was
developed using the existing IBM RS/6000 CPU, but squeezing it onto one chip.
Naturally, this could be done only by leaving out some of the features (the
PowerPC instruction set is only a subset of the RS/6000 CPU ones). So the
PowerPC chip is significant slower than the IBM RS/6000 CPU.
Currently, I can provide only data for a small benchmark programme, which
has been proven in the past that it reflects the real performance of com-
putional chemistry codes quite good. When I get an ab initio programme running
on my Pentium, I can provide more information.

c
c  Computer            Time    %          Compiler/Option
c                      sec    VAX
c-------------------------------------------------------------------------------
c  CRAY Y-MP2E/164   0.00641 28081        cf77 -Zv -Wf -o scalar -o vector
c  IBM RISC 6000/370   0.015 12000        f77 -O
c  CRAY 1              0.022  8182
c  SG Indigo (R4000)   0.025  7200        f77 -O2
c  IBM RISC 6000/350   0.026  6923        f77 -O
c  IBM RISC 6000/550   0.026  6923        f77 -O
c  IBM RISC 6000/340   0.032  5625        f77 -O
c  IBM RISC 6000/530   0.043  4186        f77 -O
c  IBM RISC 6000/320H  0.044  4091        f77 -O
c  IBM RISC 6000/320   0.053  3396        f77 -O
c  IBM 3090            0.059  3051        Optimization compiler
c  SG Indigo (R3000)   0.07   2571        -O3
c  SG Indigo (R4000)   0.073  2466        f77
c  Pentium (60 MHz)    0.08   2250        Linux f2c + gcc -O
c

Joerg-R. Hill

--------------------------------------------------------------------------------
Dr. Joerg-Ruediger Hill   | Every attempt to employ mathematical methods in the
Biosym Technologies, Inc. | study of chemical questions must be considered pro-
9685 Scranton Road        | foundly irrational  and  contrary  to the spirit of
San Diego, CA 92121-3752  | chemistry ...  If mathematical analysis should ever
USA                       | hold a prominent place in chemistry - an aberration
                          | which  is  happily  almost  impossible  -  it would
Phone (619) 546-5508      | occasion  a rapid  and  widespread  degeneration of
Fax   (619) 458-0136      | that science.
E-mail [email-masked]     |                                      A. Comte, 1830
--------------------------------------------------------------------------------
 The opinions expressed in this message are my personal opinions and no offical
 statements of Biosym Technologies, Inc. For informations about Biosym products
 send mail to: [email-masked].
--------------------------------------------------------------------------------