NEC-LIST: NEC4 Optimum Desktop Platform

Hello, everyone. For about five years now I have run f77-compiled
NEC4 on an HP Apollo 755 workstation. I am looking to replace this
workstation with newer desktop hardware and would like to have the
capability to run a 20,000 (twenty thousand) segment (assuming some
symmetry) problem in less than 24 hours on equipment dedicated to
this task. Some specs on on my HP 755:

--99 MHz PA-RISC 7100 Processor (124 MIPS, 147 SPECmarks, 40 MFLOPS)

--768 MB total RAM, 256 KB instruction cache, 256 KB data cache

I would appreciate the benefit of any experiences that you can share
regarding the above and your recommendations of platform, OS, and f77
compiler. I'd like to keep the total cost around $10k-$15k. I'm
most interested in computational speed and numerical accuracy.
Thanks for your time and any comment. Sincerely,

-- 
       __    __     ______       __   John Wood
      /  |\ / /\   / ____ \     / /\  Code 5551
     / | ||/ / /  / /\__/ /|   / / /  U.S. Naval Research Lab
    / /| |/ / /  / /_/_/ / /  / / /   4555 Overlook Avenue, SW
   / / |   / /  / ___   / /  / / /    Washington, DC 20375-5337
  / / /|  / /  / /\_| |\_/  / /_/_    (202) 767-2608
/_/ / |_/ /  /_/ / |_||   /_____/\   (202) 767-3377 (FAX)
\_\/  \_\/   \_\/  \_\|   \_____\/   e-mail: wood_at_itd.nrl.navy.mil
                                      WWW: http://server5550.itd.nrl.navy.mil
ITS NEVER SAFE TO BE NOSTALGIC ABOUT SOMETHING UNTIL YOU'RE 
ABSOLUTELY CERTAIN THERE'S NO CHANCE OF ITS COMING BACK. - Bill Vaughn