Christopher, when we ran on 4000 processors for a global 1/16th configuration, we used: cg2dMaxIters=100, cg2dTargetResidual=1.E-5, D. -- Dimitris Menemenlis <menemenlis at sbcglobal.net> 5056 Oakwood Ave, La Canada, CA 91011-2450 tel/fax: 818-790-6735; cell: 818-625-6498