QPACE is a novel massively parallel architecture optimized for lattice QCD simulations. Each node comprises an IBM PowerXCell 8i processor. The nodes are interconnected by a custom 3-dimensional torus network implemented on an FPGA. The architecture was systematically optimized with respect to power consumption. This put QPACE in the number one spot on the Green500 List published in November 2009. In this paper we give an overview of the architecture and highlight the steps taken to improve power efficiency.

The IBM BladeCenter® QS22 is a blade server that is based on two IBM PowerXCell™ 8i processors. This server is the successor of the QS21 server, which delivered excellent multicore Cell Broadband Engine® (Cell/B.E.) performance for workstation, server, and supercomputer customers. The IBM PowerXCell 8i processor represents a second generation of the Cell Broadband Engine Architecture. It significantly improves floating-point performance and allows for larger memory configurations. In this paper, we provide an overview of the architecture and design of this newer QS22 system and explain some of the design decisions. We discuss hardware and application performance, power efficiency, manageability, and configuration options, and how these factors affect hybrid system configurations. Finally, we briefly describe two hybrid system configurations that utilize the QS22 system. One configuration involves the Roadrunner system at Los Alamos National Laboratory, the first one-petaflops supercomputer in the world. The second configuration involves a hybrid system with a PCI Express® switch used for coupling.

We give an overview of the QPACE project, which is pursuing the development of a massively parallel, scalable supercomputer for LQCD. The machine is a three-dimensional torus of identical processing nodes, based on the PowerXCell 8i processor. The nodes are connected by an FPGA-based, application-optimized network processor attached to the PowerXCell 8i processor. We present a performance analysis of lattice QCD codes on QPACE and corresponding hardware benchmarks.

QPACE is a novel parallel computer which has been developed to be primarily used for lattice QCD simulations.The compute power is provided by the IBM PowerXCell 8i processor, an enhanced version of the Cell processor that is used in the Playstation 3. The QPACE nodes are interconnected by a custom, application optimized 3-dimensional torus network implemented on an FPGA.To achieve the very high packaging density of 26 TFlops per rack a new water cooling concept has been developed and successfully realized.In this paper we give an overview of the architecture and highlight some important technical details of the system.Furthermore, we provide initial performance results and report on the installation of 8 QPACE racks providing an aggregate peak performance of 200 TFlops.