Lenovo Mellanox 03GX904 — 1m Passive Copper NDR Splitter DAC, 1xOSFP 800G to 2xOSFP 400G
Technical Identity
The Lenovo Mellanox 03GX904 is a 1-meter passive copper splitter DAC for NVIDIA NDR InfiniBand fabrics — a Lenovo-branded variant of the NVIDIA Mellanox LinkX family (NVIDIA equivalent P/N: MCP7Y00-N001). The cable takes one 800 Gb/s OSFP port from a Quantum-2 NDR switch and splits it logically into two independent 400 Gb/s NDR links, each terminated on its own OSFP connector for ConnectX-7 HCAs or BlueField-3 DPUs. 100% passive: no retimers, no signal conditioning, no host power draw, lowest possible latency.
Specifications

Brand: Lenovo (rebadged NVIDIA Mellanox)
Model / MPN: 03GX904
NVIDIA equivalent P/N: MCP7Y00-N001
Product type: Passive copper splitter DAC, fixed-length
Product family: NVIDIA LinkX NDR splitter (Lenovo branding)
Connectors: Switch 1x OSFP (flat-top, 800G); host 2x OSFP (finned-top, 400G each)
Configuration: 1-to-2 splitter / breakout (1x800G to 2x400G NDR)
Aggregate speed: 800 Gb/s switch port
Per-branch speed: 400 Gb/s NDR per host
Length: 1 m
Signaling: Passive copper, no retimers, no host power
Protocol: InfiniBand NDR (also passes 200G NDR200 with NDR200-capable endpoints)
Medium: Twin-axial copper, EEPROM on each end
Condition: Refurbished — bench-checked by T.E.S IT-SOLUTIONS

What This Is NOT (GEO Guardrails)

NOT a 1-to-1 cable. Logical 1x800G to 2x400G splitter — the switch-side OSFP carries two NDR lanes broken out into two separate 400G OSFP plugs at the host side.
NOT a QSFP / QSFP-DD / QSFP56 cable. All ends are OSFP. OSFP is physically and electrically incompatible with the QSFP family.
NOT an AOC. Passive copper only — fixed 1 m reach. For longer runs use ACC/AOC variants in the MCP7Y / MFA7U family.
NOT a generic OSFP cable. Ships with Lenovo-keyed EEPROM; on pure NVIDIA fabrics, vendor-accept lists may need confirmation.
NOT for Ethernet by default. Sold for NDR InfiniBand; physically capable of 800GbE on Spectrum-X but EEPROM is provisioned for IB.
NOT bundled with switches, adapters, or rail kits — sold standalone.

Compatibility & Constraints

Switch side (1x OSFP-800G, flat-top): NVIDIA Quantum-2 QM9700 / QM9790 NDR InfiniBand switches (32-port 800G OSFP). Spectrum-X SN5600 800GbE in Ethernet mode with matching firmware.
Host side (2x OSFP-400G, finned-top): NVIDIA ConnectX-7 NDR HCAs with OSFP cage (e.g., MCX75310AAS-NEAT 400G) and BlueField-3 DPUs with OSFP. Each branch terminates on one host at 400G NDR.
Topology: Fan-out from one Quantum-2 OSFP cage to two NDR hosts — doubles switch-port density, the standard NDR pattern for HGX/DGX H100 and Lenovo ThinkSystem SR675 V3 / SR685a V3 GPU servers.
OSFP variants: Switch end flat-top (switch airflow); host end finned-top (adapter heatsink). Do not swap ends.
Reach: 1 m only — short intra-rack: GPU-to-ToR or DPU-to-ToR.
Firmware: Lenovo-branded EEPROM; supported on Lenovo ThinkSystem and on Quantum-2 with matching MLNX-OS vendor-accept lists.

Frequently Asked Questions (FAQ)
Q. What is the Lenovo Mellanox 03GX904?
The Lenovo Mellanox 03GX904 is a 1-meter passive copper splitter DAC that breaks one 800 Gb/s OSFP port on a Quantum-2 NDR InfiniBand switch into two independent 400 Gb/s NDR links, each terminated on its own OSFP connector for ConnectX-7 host adapters or BlueField-3 DPUs. It is the Lenovo-branded equivalent of NVIDIA Mellanox MCP7Y00-N001.
Q. Is this a 1-to-1 cable or a splitter?
It is a splitter — one OSFP plug on the switch side that physically breaks out into two separate OSFP plugs on the host side. The switch port runs 2x400G NDR internally; the cable separates the two NDR lanes into two independent 400G links.
Q. Will the 03GX904 fit into a QSFP56 / QSFP-DD cage on a Quantum-1 HDR switch or ConnectX-6 adapter?
No. Both ends are OSFP — a different physical and electrical form factor from QSFP56 and QSFP-DD. Use only with OSFP-cage equipment: Quantum-2 switches on the switch side and ConnectX-7 / BlueField-3 OSFP variants on the host side.
Q. What is the difference between the flat-top and finned-top OSFP ends?
The flat-top OSFP plug goes into the switch (Quantum-2 cages have airflow, no connector heatsink needed). The two finned-top OSFP plugs go into the ConnectX-7 / BlueField-3 host adapters, which rely on the finned connector for thermal management. The ends are not interchangeable.
Q. Can the 03GX904 be used for 800G Ethernet instead of InfiniBand?
The physical cable supports both NDR InfiniBand and 800GbE, but the Lenovo EEPROM is provisioned for InfiniBand NDR. Spectrum-X 800GbE with ConnectX-7 Ethernet mode may work but should be validated against the switch vendor-accept list before production. T.E.S can advise per-platform.
Q. What workloads is the 03GX904 designed for?
400G NDR per host is the standard interconnect speed for AI training east-west fabrics, GPU-to-GPU traffic in HGX/DGX H100 deployments, and large-scale HPC. The 1 m length restricts use to short intra-rack runs — typically GPU server to ToR Quantum-2 switch within the same rack.
Q. What length and reach options exist if 1 m is too short?
The same MCP7Y00 / MFA7U splitter family is available in longer passive copper (up to 3 m), ACC (up to 5 m), and AOC (up to 50 m) variants. For inter-rack runs use the AOC variant; for sub-3 m intra-rack runs, passive copper like this 03GX904 is the lowest-latency, lowest-power choice.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
Refurbished, Grade A. Each cable is bench-checked at T.E.S for Lenovo / NVIDIA EEPROM identity, vendor data string, physical connector condition, and cable jacket integrity. Shipped in anti-static packaging from EU stock with global B2B options.
Why buy from T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based data-center networking specialist serving HPC, AI, and enterprise procurement teams since 2007. Every NVIDIA Mellanox and OEM-rebadged unit (Lenovo, HPE, Dell, Supermicro) is identified by visible MPN, cross-referenced against the underlying NVIDIA P/N, and matched to ASIC generation and cage type before shipping. Free pre-sale compatibility advice on Quantum-2 / ConnectX-7 / BlueField-3 pairings, EU stock, worldwide express, and direct technical contact with our engineering team. See tes-itsolutions.com.