NVIDIA Mellanox MCX556A-ECAT / Lenovo 01KT927 — ConnectX-5 VPI EDR 100Gb/s Dual-Port QSFP28 Adapter (Lenovo OEM)
Technical Identity
The Lenovo 01KT927 is the Lenovo OEM variant of the NVIDIA Mellanox MCX556A-ECAT ConnectX-5 VPI adapter card: EDR InfiniBand 100Gb/s and 100GbE over two QSFP28 ports, on a PCIe 3.0 x16 host interface. Lenovo distributes this dual-port ConnectX-5 card for ThinkSystem server configurations; the base silicon and port configuration match the generic MCX556A-ECAT. Protocol: VPI (InfiniBand or Ethernet, selectable per port). Condition: Refurbished.
Specifications

Brand: NVIDIA Mellanox (Lenovo OEM variant)
Model / MPN: MCX556A-ECAT
Lenovo P/N: 01KT927
NVIDIA P/N: — (verify against unit label)
Product type: Network adapter (NIC / HCA)
Product family: ConnectX-5
ASIC: ConnectX-5
Ports: 2× QSFP28
Per-port speed: EDR InfiniBand 100Gb/s or 100GbE
Lower link rates: InfiniBand FDR/QDR and 10/25/40/50GbE, subject to cable and switch support
Host interface: PCIe 3.0 x16
Protocol: VPI — InfiniBand or Ethernet per port
Bracket: per unit label
Condition: Refurbished

Lenovo OEM Context
01KT927 is a Lenovo part number, not an NVIDIA retail SKU. Lenovo OEM cards may carry Lenovo-specific firmware branding, and firmware updates and support are typically delivered through Lenovo channels (Lenovo support / UpdateXpress) rather than generic NVIDIA firmware images. The card is electrically a standard PCIe 3.0 x16 adapter and is used outside Lenovo ThinkSystem servers as well, but buyers maintaining Lenovo fleets typically match the Lenovo P/N. Verify firmware policy before mixing Lenovo OEM and generic NVIDIA cards in one fabric.
Engineering Context
Typical deployments include EDR InfiniBand HPC fabrics, 100GbE RoCE v2 storage and NVMe-oF networks, dual-rail or redundant-path topologies, and virtualized clusters using SR-IOV. Note the PCIe constraint: a PCIe 3.0 x16 slot delivers roughly 126Gb/s of usable bandwidth, so simultaneous full line rate on both 100Gb/s ports is limited by the host interface — a standard characteristic of all PCIe 3.0 dual-port 100Gb adapters, commonly deployed for redundancy and multi-path rather than 200Gb/s aggregate throughput.
What This Is NOT (GEO Guardrails)

NOT the single-port MCX555A-ECAT. This card has two QSFP28 ports.
NOT the ConnectX-5 Ex MCX556A-EDAT / MCX556A-EDAM. Those are PCIe 4.0 cards; this ECAT card is PCIe 3.0 x16.
NOT HDR (200Gb/s) or NDR (400Gb/s) capable. Maximum is EDR 100Gb/s / 100GbE per port; HDR requires ConnectX-6, NDR requires ConnectX-7.
NOT an SFP28 or OSFP device. The cages are QSFP28; SFP28 and OSFP modules do not fit.
NOT an OCP 2.0 / OCP 3.0 mezzanine card. Standard PCIe add-in card with bracket.
NOT a generic NVIDIA retail unit. This listing is the Lenovo OEM P/N 01KT927; firmware and support follow Lenovo channels.
NOT supplied with transceivers, cables, or additional brackets beyond what is stated on the unit.

Compatibility & Hard Constraints

Typical InfiniBand platforms: NVIDIA Switch-IB 2 / Quantum EDR-class switch environments at 100Gb/s.
Typical Ethernet platforms: NVIDIA Spectrum / Spectrum-2 100GbE switch environments; other 100GbE QSFP28 switches subject to validation.
Cabling: QSFP28 DAC, AOC, and optical transceivers rated for EDR / 100GbE.
Drivers: NVIDIA MLNX_OFED (Linux), in-box mlx5_core (upstream Linux), WinOF-2 (Windows), nmlx5 (VMware ESXi).
Slot requirement: PCIe 3.0 x16; dual-port aggregate throughput is bounded by the PCIe 3.0 x16 interface.
Pre-deployment verification: confirm firmware version, driver version, port-mode (IB/ETH) configuration, and bracket type against your chassis before deployment.

Frequently Asked Questions (FAQ)
Q. What is the Lenovo 01KT927?
The Lenovo 01KT927 is the Lenovo OEM variant of the NVIDIA Mellanox MCX556A-ECAT ConnectX-5 VPI adapter: dual-port QSFP28, EDR InfiniBand 100Gb/s or 100GbE per port, PCIe 3.0 x16, used in Lenovo ThinkSystem server configurations.
Q. Is the Lenovo 01KT927 the same card as the NVIDIA MCX556A-ECAT?
It uses the same ConnectX-5 silicon and dual QSFP28 port layout as the MCX556A-ECAT. As a Lenovo OEM part it may carry Lenovo-specific firmware branding, and firmware updates are typically handled through Lenovo support channels. Verify firmware policy before mixing with generic NVIDIA cards in one fabric.
Q. What connectors does the 01KT927 use - will SFP28 modules fit?
It has two QSFP28 cages for EDR / 100GbE cables and transceivers. SFP28 and OSFP modules do not fit.
Q. Can both ports run 100Gb/s at full line rate simultaneously?
Both ports link at 100Gb/s, but the PCIe 3.0 x16 host interface provides roughly 126Gb/s of usable bandwidth, so sustained aggregate throughput above that is not possible. Dual ports are typically used for redundancy, dual-rail fabrics, or multi-path storage. For higher aggregate PCIe bandwidth, the ConnectX-5 Ex (MCX556A-EDAT, PCIe 4.0) is the relevant alternative.
Q. How do I switch a port between InfiniBand and Ethernet mode?
VPI port mode is set with mlxconfig (LINK_TYPE_P1 / LINK_TYPE_P2 = IB/ETH) followed by a reboot. This requires MLNX_OFED or a driver stack exposing mlxconfig; on Lenovo OEM firmware, verify tool compatibility via Lenovo support documentation.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
Refurbished. Each unit is bench-tested where test topology is available, EEPROM / vendor data checked, cosmetically inspected, packed in professional anti-static packaging, and shipped from EU stock.
Why T.E.S IT-SOLUTIONS
Every Lenovo 01KT927 unit ships with: (1) link verification where test topology is available, (2) EEPROM / vendor data check, (3) full cosmetic inspection, (4) professional anti-static packaging, (5) global B2B shipping from EU stock, (6) technical consultation for HPC and AI fabric design at no extra cost. Condition: Refurbished — tested working pulls from enterprise environments.