Parallel programs (XPLOR, SHELX-L)?

[Hartmut "Hudel" Luecke]

We are in the process of acquiring a 16 to 64 processor
parallel machine with about 2 GB of main memory.

I am looking for information on which of the crystallographic
programs that tend to be very CPU intensive (such as long
molecular dynamics runs, high resolution refinement 
with SHELX-L) have been ported/optimized to parallel machines
such as the SGI Origin2000.  I would like to know how
their respective performance scales with the number of processors.

I would also like to hear about comments on which
of the current multi-processor systems (IBM, HP, SGI, DEC etc.)
is most user-friendly (in terms of programming as well
as running programs).

Thanks, Hudel

H. Luecke
Molecular Biology & Biochemistry
UC Irvine
HUDEL at UCI.EDU