Increasing convergence rate

[jerome ho]

Hi

I'm trying to simulate with different solvers in order to have range of options.
The matrix is sparse and square, and eventually will be used for
parallel simulation.
These are the results:

boomeramg+minres: 388MB in 1min (8 iterations)
icc+cg: 165MB in 30min  (>5000 iterations)
bjacobi+cg: 201MB in 50min (>5000 iterations)

There are several others but it takes >5000 iterations to achieve the
boomeramg+minres result.
Boomeramg result is good, but takes too high memory.
I wonder if there're any options, or any better precondition+solver
combination that I should use
in order to improve the runtime of the non-boomeramng simulation.

Jerome
--