Early Evaluation of the Cray X1

Oak Ridge National Laboratory installed a 32 processor Cray X1 in March, 2003, and will have a 256 processor system installed by October, 2003. In this paper we describe our initial evaluation of the X1 architecture, focusing on microbenchmarks, kernels, and application codes that highlight the performance characteristics of the X1 architecture and indicate how to use the system most efficiently.