Dell 0R5WK9 — Mellanox ConnectX-6 Lx Dual-Port 25GbE SFP28 Adapter
Technical Identity
Dell OEM Mellanox ConnectX-6 Lx EN network adapter (Dell PN 0R5WK9): dual-port 25GbE SFP28, PCIe 4.0 x8, standard PCIe add-in form factor. Dell PowerEdge qualified. Hardware offloads include RoCE v2, NVMe-oF over RoCE, VXLAN/NVGRE/Geneve overlay acceleration, SR-IOV, and PTP/SyncE timing. ConnectX-6 Lx is the Ethernet-only Lx silicon — no InfiniBand support. Condition: Refurbished Grade A, EU stock.
Specifications

Brand: Dell (OEM Mellanox ConnectX-6 Lx EN)
Dell PN: 0R5WK9
ASIC: ConnectX-6 Lx (Ethernet-only Lx)
Ports: 2× 25GbE SFP28
Protocol: Ethernet only (10/25 GbE)
Host interface: PCIe 4.0 x8 (backward compatible with PCIe 3.0)
Form factor: Standard PCIe add-in (low-profile + full-height brackets)
Qualification: Dell PowerEdge
Offloads: RoCE v2, NVMe-oF, VXLAN/NVGRE/Geneve, SR-IOV, PTP/SyncE
Condition: Refurbished Grade A

What This Is NOT

NOT InfiniBand. Ethernet EN only (ConnectX-6 Lx is Ethernet-only silicon — no VPI, no IB mode).
NOT 100GbE. 25GbE max per port. For 100GbE Dell-OEM ConnectX-6, see 0F6FXM / equivalent.
NOT an OCP 3.0 card. Standard PCIe add-in only. For OCP 3.0 mezzanine, see 0DN78C.
NOT a generic NVIDIA retail card. Dell OEM firmware/PSID — verify boot in non-Dell chassis before deploying at scale.
NOT supplied with SFP28 transceivers, DAC, AOC cables, or extra brackets.

Compatibility & Constraints

Servers: Native Dell PowerEdge (14G/15G/16G — R640, R740, R750, R760, etc.). Operation in HPE/Lenovo/SuperMicro may be restricted by Dell PSID — bench-test first.
Switches: Pairs with NVIDIA Spectrum / Spectrum-2 / Spectrum-3 25GbE switches (SN2010, SN2410, SN3700C) and Cisco Nexus 9300, Arista 7050X / 7280R 25GbE ToR.
Interconnect: SFP28 25GbE DAC (passive copper) up to 3m, 25GbE AOC up to 30m, or SFP28 25GbE SR/LR optical transceivers — sold separately.
OS / Drivers: Dell-signed firmware. Inbox driver in RHEL 8/9, Ubuntu 20.04/22.04, ESXi 7/8, Windows Server 2019/2022. MLNX_OFED / WinOF-2 supported.
Verify before deploying: PSID, firmware revision, and switch ToR port mode (25G vs 10G auto-neg) must align.

Frequently Asked Questions (FAQ)
Q. What is the Dell 0R5WK9?
Dell OEM ConnectX-6 Lx: dual-port 25GbE SFP28. PowerEdge qualified. RoCE v2, NVMe-oF, SR-IOV.
Q. Is 0R5WK9 InfiniBand capable?
No — Ethernet EN only (ConnectX-6 Lx EN).
Q. How does 0R5WK9 compare to 0DN78C?
0R5WK9 = standard PCIe add-in. 0DN78C = OCP 3.0 mezzanine. Both dual 25GbE SFP28 ConnectX-6 Lx.
Q. Can 0R5WK9 be used in non-Dell servers?
Possibly — OEM firmware/PSID may restrict. Verify before deploying.
Q. What condition does T.E.S supply?
Refurbished Grade A — EEPROM-verified, link-tested, EU stock.
Why buy from T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based data-center networking specialist. Every unit is MPN-identified, EEPROM-verified, link-tested, and cosmetically inspected before leaving our EU warehouse. Multi-currency invoicing, worldwide express shipping, and free pre-sale technical consultation for switch / adapter / cable pairing included.