[Wien] What type of CPU's for big calculations?

[Laurence Marks]

I am considering purchasing some nodes for bigger calculations. Wien2k
is very efficient for parallelizing one k-point per node, but not very
efficient with mpi. Unfortunately the benchmarks are currently for a
relatively small calculation.

1) Has anyone tested big cases (e.g. matrix sizes more than 14000,
perhaps as high as 25000) on the newer CPU's with more RAM?
2) Does one have to have a 64bit system for big cases.
3) Does threading the cores really matter with big matrices
(OMP_NUM_THREADS=2) ?
4) What about the specifics of the memory architecture (shared versus
independent) and the L2 cache (size and whether it is shared)?
5) Has anyone tried running two jobs each with two threads to a two
CPU dual-core machine (four effective cores) -- or does the OS get
confused about who does what?

-- 
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
http://www.numis.northwestern.edu