Microsoft X899301-002 Mellanox ConnectX-3 Pro EN Single-Port 40GbE QSFP NIC for Windows Cloud Server (WCS): This is a Microsoft Open CloudServer / Windows Cloud Server (WCS) network adapter identified by Microsoft P/N X899301-002 and built on Mellanox ConnectX-3 Pro EN silicon. The card provides a single 40 Gigabit Ethernet QSFP port and was originally deployed in Microsoft hyperscale infrastructure. This is NOT a standard retail PCIe NIC and NOT a multi-port adapter; it is a single-port card targeted at Microsoft's Open CloudServer chassis. This is a Refurbished unit, professionally tested by T.E.S IT-SOLUTIONS.
Engineering Context
ConnectX-3 Pro adds NVGRE and VXLAN stateless overlay offloads, RDMA over Converged Ethernet (RoCE), and SR-IOV virtualization to the standard ConnectX-3 EN feature set. The single QSFP port operates at 40 GbE Ethernet line rate. The host interface is PCI Express 3.0 x8, providing approximately 63 Gbps of usable bandwidth — sufficient for full 40 GbE line rate plus headroom. The card is engineered for Microsoft's Open CloudServer (WCS) blade form factor used in Microsoft data centers.
Deployment & Use Cases
Microsoft Open CloudServer / WCS chassis spare or expansion. Hyperscale Ethernet fabrics needing a single-port 40 GbE NIC with VXLAN/NVGRE offload. RoCE-accelerated storage interconnect over 40 GbE. Lab or development environments that mirror Microsoft hyperscale rack hardware. Bulk supply for facilities migrating Microsoft WCS hardware into private cloud deployments.
Technical Specifications
OEM: Microsoft
Microsoft P/N: X899301-002
Underlying Controller: Mellanox ConnectX-3 Pro EN
Product Line: ConnectX-3 Pro
Form Factor: Microsoft WCS / Open CloudServer NIC
Number of Ports: 1
Connector: QSFP (QSFP+ compatible)
Line Rate: 40 GbE
Host Interface: PCI Express 3.0 x8
Overlay Offloads: VXLAN, NVGRE
RDMA: RoCE
SR-IOV: Supported
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Designed for Microsoft Open CloudServer (WCS) blade chassis. Compatible with Mellanox MLNX_OFED, WinOF, and standard upstream Linux ConnectX-3 drivers — verify firmware compatibility for non-Microsoft host platforms. The card uses a Microsoft-specific form factor and may NOT seat directly into standard PCIe slots without a compatible carrier or chassis. Will NOT operate as InfiniBand (this is the EN variant — Ethernet only). Does NOT support 100 GbE — this is a 40 GbE-only adapter. QSFP cables and switches must be sourced separately.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS specializes in refurbished enterprise networking from NVIDIA Mellanox and OEM-rebadged variants. Each Microsoft WCS card is professionally tested by experienced technicians. Browse our refurbished NIC catalog. Standard handling time is 1–3 business days.