The HP 4X QDR InfiniBand Mezzanine HCA for c-Class BladeSystem is based on the Mellanox ConnectX-2 technology. The QDR IB HCA delivers low-latency and up to 40 Gbps (QDR) bandwidth for performance-driven server and storage clustering applications in High-Performance Computing (HPC) and enterprise data centers. Parallel or distributed applications running on multi-processor multi-core servers will benefit from the reliable transport connections, advanced multicast support and collective offload offered by ConnectX-2 technology. End-to-end Quality of Service (QoS) enables partitioning and guaranteed service levels while hardware-based congestion control prevents hot spots from degrading the effective throughput. The HP 4X QDR IB CX-2 Dual-port Mezzanine HCA card is designed for PCI Express 2.0 x8 connectors on HP BladeSystem c-Class G6 server blades.