The HP 4X QDR IB Dual-port Mezzanine HCA for HP BladeSystem c-Class is based on the Mellanox ConnectX IB technology. The QDR IB HCA delivers low-latency and up to 40Gbps (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 and advanced multicast support offered by ConnectX IB. 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 Dual-port Mezzanine HCA card is designed for PCI Express 2.0 x 8 connectors on HP BladeSystem c-Class G6 server blades.