Manufacturer's description and specifications:

Intel® Ethernet Server Adapters X520 Dual- and Single-Port 10 Gigabit SFP+ Ethernet Server Adapters Provide Ultimate Flexibility and Scalability in Virtual and Unified Storage Environments.

Intel’s family of Intel® Ethernet Server Adapters X520 with SFP+ connectivity are the most flexible and scalable Ethernet adapters for today’s demanding data center environments. Data center networks are being pushed to their limits. The escalating deployments of servers with multi-core processors and demanding applications such as high performance computing (HPC), database clusters, and video-on-demand are driving the need for 10 Gigabit connections. Customers require flexible and scalable I/O solutions to meet the rigorous requirements of running mission-critical applications in virtualized and unified storage environments. Powered by Intel’s third-generation 10 GbE network controller, the Intel® Ethernet 82599 10 Gigabit Ethernet Controller, the X520 server adapter family addresses the demanding needs of the next-generation data center by providing unmatched features for virtualization, flexibility for LAN and SAN networking, and proven, reliable performance.

• Product P/N: X520-LR1
• Product Collection: 500 Series Network Adapters (up to 10GbE)
• Launch Date: Q3'09
• Vertical Segment: Server
• Cable Medium: Fiber
• Cabling Type: SMF up to 10km
• Bracket Height: Low Profile and Full Height
• Product Order Code: E10G41BFLR

• Port Configuration: Single
• Data Rate Per Port: 10/1GbE
• Intel® Virtualization Technology for Connectivity (VT-c): Yes
• Speed & Slot Width: 5.0 GT/s, x8 Lane
• Controller: Intel® 82599 10 Gigabit Ethernet Controller

• System Interface Type: PCIe v2.0 (5.0 GT/s)

• On-chip QoS and Traffic Management: Yes
• Flexible Port Partitioning: Yes
• Virtual Machine Device Queues (VMDq): Yes
• PCI-SIG* SR-IOV Capable: Yes

• iWARP/RDMA: No
• Intel® Data Direct I/O Technology: Yes
• Intelligent Offloads: Yes
• Storage Over Ethernet: iSCSI, NFS