released blades, conventional rack servers and PCI Express accelerator boards with Cell processors. In the fall of 2006, IBM released the QS20 blade module using double Cell BE processors for tremendous performance in certain applications, reaching a peak of 410 gigaFLOPS in FP8 quarter precision per module. The QS22 based on the PowerXCell 8i processor was used for the IBM Roadrunner supercomputer. Mercury and IBM uses the fully utilized Cell processor with eight active SPEs. On April 8, 2008, Fixstars Corporation released a PCI Express accelerator board based on the PowerXCell 8i processor. Sony's high-performance media computing server ZEGO uses a 3.2 GHz Cell/B.E processor. Overview The Cell Broadband Engine, or Cell as it is more commonly known, is a microprocessor intended as a hybrid of conventional desktop processors (such as the Athlon 64, and Core 2 families) and more specialized high-performance processors, such as the NVIDIA and ATI graphics-processors (GPUs). The longer name indicates its intended use, namely as a component in current and future online distribution systems; as such it may be utilized in high-definition displays and recording equipment, as well as HDTV systems. Additionally the processor may be suited to digital imaging systems (medical, scientific, etc.) and physical simulation (e.g., scientific and structural engineering modeling). In a simple analysis, the Cell processor can be split into four components: external input and output structures, the main processor called the Power Processing Element (PPE) (a two-way simultaneous-multithreaded PowerPC 2.02 core), eight fully functional co-processors called the Synergistic Processing Elements, or SPEs, and a specialized high-bandwidth circular data bus connecting the PPE, input/output elements and the SPEs, called the Element Interconnect Bus or EIB. To achieve the high performance needed for mathematically intensive tasks, such as decoding/encoding MPEG streams, generating or transforming three-dimensional data, or undertaking Fourier analysis of data, the Cell processor marries the SPEs and the PPE via EIB to give access, via fully cache coherent DMA (direct memory access), to both main memory and to other external data storage. To make the best of EIB, and to overlap computation and data transfer, each of the nine processing elements (PPE and SPEs) is equipped with a DMA engine. Since the SPE's load/store instructions can only access its own local scratchpad memory, each SPE entirely depends on DMAs to transfer data to and from the main memory and other SPEs' local memories. A DMA operation can transfer either a