Chathuri Samarasinghe. Janelle Doebel Andrew Azzam P Elaheh Gorgin Beini Jiang P Yao Xue P X Dave Kamin John Asplund P Quingfu Feng F Allan Struthers FP Le Zhang (Adam) F The Convergence of SOR Relaxation for the Poisson Equation Allan Struthers, Math Sciences, Michigan Tech Large sparse linear system that arises from finite difference discretizations of Poisson's equation are standard test problems for iterative linear solvers with SOR (Successive Over Relaxation)- using optimal (or near optimal) values of the relaxation parameter - frequently used as a benchmark. This presentation will describe some surprising behavior (and the linear algebra explanation for it) observed when developing such a benchmark.