NEC-LIST: NEC4 Optimum Desktop Platform

Dear John Ross & other CEMists,

Further to my earlier contribution on running NEC on a PC, I have run
the following input file on a Pentium III 800MHz PC:

CE Timing test - Multiple parallel wires, 20000 segments, 2 planes symmetry
GW0,100,.2,.2,0.,.2,.2,10.,.001
GM0,9,0.,0.,0.,.2,0.,0.
GM0,4,0.,0.,0.,0.,.2,0.,0.
GX0,110
GE
EX0,0,5,0,1.
XQ
EN

This file is based on a 1200 segment one used by Jerry Burke in his
Modellers Notes column in the ACES Newsletter a few years back, as a
benchmark test. The above uses a series of parallel wires totalling
5000 segments, which is reflected in both the X and Y axes. This
provides 20000 segments with four-fold symmetry, which is what I
believe you are interested in, John.

On the P800, single processor, the run times in seconds were as
follows: Fill:350; Factor:2340; Total:2760 (46mins). The total memory
requirement was 800MB for single precision. I don't think the
Intel/AMD platforms should be dismissed too lightly. The main
limitation is the maximum RAM that can be accommodated in the
motherboard. As far as I know, the upper limit is probably 2GB, but
if you can manage with this, the speed can be quite good.

Incidentally, the speed improvement due to introducing LAPACK seems
much more marked for the Intel/AMD processor (for which around a
12-fold increase is evident) than for the HP C3600 mentioned by
Jeurgen (3-fold).

The Intel/AMD solution may still not be as fast as a 64bit workstation
processor, but you can't 'arf buy a lot of 'em for the same money! If
I have four runs to complete, I can run four machines side by side.
The Pentium 4 processor now comes at up to 1.4GHz, although I am not
sure how the P3 and P4 compare for a given clock speed. I have heard
that without the software to take advantage of it, the P4 is a few
percent slower than the P3 after adjusting for clock speed. However,
the latest version of Compaq Visual Fortran (v6.5) includes
optimisation for the P4, but I don't know what advantage it offers.

I would be interested in seeing how fast the 20000 segment model above
runs on other platforms.

Regards,

Paul Carlier
FanField Ltd.
Braxted Park
Witham
Essex CM8 3XB England
(Tel. +44 (0) 1621 893500)
www.fanfield.co.uk
Received on Sun Feb 18 2001 - 18:01:28 EST