An efficient parallel iterative method for unstructured grids developed by the authors for SMP cluster architectures on the GeoFEM platform is presented. The method is based on a 3-level hybrid parallel programming model, including message passing for inter-SMP node communication, loop directives by OpenMP for intra-SMP node parallelization and vectorization for each processing element (PE). Simple 3D elastic linear problems with more than 8×108 DOF have been solved by 3x3 block ICCG(0) with additive Schwarz domain decomposition and PDJDS/CM-RCM reordering on 128 SMP nodes of Hitachi SR8000/MPP parallel computer, achieving performance of 335.2 GFLOPS. The PDJDS/CM-RCM reordering method provides excellent vector and parallel performance in SMP nodes.