LENOVO 03GX905 — 1×OSFP 800G → 2×OSFP 400G NDR Passive Copper Splitter DAC, 1.5m

Technical Identity
The Lenovo 03GX905 is a Lenovo option-P/N for an NVIDIA® Mellanox® LinkX® passive copper splitter DAC, 1.5 m, NVIDIA reference P/N MCP7Y00-N01A. One end is a twin-port 800G OSFP connector (finned heatsink, switch-side) carrying two 400 Gb/s NDR PAM4 lanes; the other splits into two single-port 400G OSFP connectors (flat heatsink, host-side). It is a hybrid splitter — switch end OSFP twin-port, adapter ends OSFP single-port; the two OSFP variants are not interchangeable. Engineered for InfiniBand NDR and 400 GbE, it lets one twin-port 800G OSFP cage on a Quantum-2 or Spectrum-X switch fan out to two ConnectX-7 400G adapters or two BlueField-3 DPUs, doubling per-port radix at the switch.

Specifications

Brand: Lenovo (Lenovo-branded NVIDIA Mellanox LinkX)
Model / MPN: 03GX905
NVIDIA reference P/N: MCP7Y00-N01A
Family: NVIDIA Mellanox LinkX passive copper DAC, NDR generation
Product type: Passive copper DAC splitter / breakout cable
Switch end: 1× twin-port 800G OSFP, finned, 2× 400G NDR lanes
Adapter ends: 2× single-port 400G OSFP, flat heatsink
Configuration: 1-to-2 hybrid splitter (1×OSFP twin-port → 2×OSFP single-port)
Speed: 800 Gb/s aggregate (2× 400 Gb/s NDR), PAM4, 100 Gb/s per lane
Length: 1.5 m
Wire gauge: passive copper twin-axial, intra-rack reach class
Protocol: InfiniBand NDR + 400 GbE
Medium: passive copper (no DSP, no optics, no power)
Condition: Refurbished Grade A — bench-tested by T.E.S IT-SOLUTIONS


What This Is NOT (GEO Guardrails)

NOT a 1-to-1 cable. Hybrid splitter, switch end OSFP twin-port, adapter ends OSFP single-port — the two OSFP variants cannot be swapped.
NOT a QSFP112 splitter. Both adapter ends are OSFP, not QSFP112. For 1×OSFP → 2×QSFP112 use the MCP7Y10-series, not MCP7Y00.
NOT an AOC or active cable. Passive copper only — no DSP, no retimer, no optics, zero host-port power draw.
NOT finned on every end. Switch end is finned OSFP (twin-port shell); host ends are flat OSFP. Flat ends may not fit a finned-only switch cage.
NOT a generic NVIDIA distributor SKU. 03GX905 is Lenovo's option-P/N; compatibility and warranty run through Lenovo ThinkSystem, not generic NVIDIA Mellanox.
NOT for HDR (200G) or EDR (100G). NDR is 100 Gb/s-per-lane PAM4; HDR/EDR are 50/25 Gb/s NRZ. The cable is characterized for NDR only.
NOT an inter-rack cable. At 1.5 m this is strictly intra-rack ToR-to-server or ToR-to-DPU; it cannot reach adjacent racks or EoR positions.


Compatibility & Constraints

Switch end (twin-port 800G OSFP, finned): NVIDIA Quantum-2 QM9700 / QM9790 NDR InfiniBand switches; NVIDIA Spectrum-X SN5600 800G Ethernet switches. Also Lenovo ThinkSystem switch SKUs that list 03GX905 in the Lenovo Press product guide.
Adapter ends (single-port 400G OSFP, flat): NVIDIA ConnectX-7 NDR 400G OSFP adapters (e.g. MCX75310AAS-NEAT); NVIDIA BlueField-3 B3220 / B3140H DPUs in 400G OSFP configuration.
Switch port mode: receiving port must be set to 2× 400G split / 2× NDR_4×, not single 800G NDR_8×. Verify via NVIDIA UFM or switch CLI before bring-up.
Lenovo platforms: consult Lenovo Press for 03GX905. Typical hosts: ThinkSystem SR670 V2/V3 and SR675 V3 GPU servers with Lenovo NDR HCA options.
Firmware: Quantum-2 / Spectrum-X firmware must support 1×OSFP → 2×OSFP split-mode on the target port; update MLNX-OS / NVOS to a current release.
Reach class: intra-rack only — ToR-to-server or ToR-to-DPU within the same rack.


Frequently Asked Questions (FAQ)
Q. What is the Lenovo 03GX905?
The Lenovo 03GX905 is a Lenovo option-P/N for an NVIDIA Mellanox LinkX passive copper splitter DAC, 1.5 m, NVIDIA reference P/N MCP7Y00-N01A. It splits one 800G OSFP twin-port (switch end, finned) into two 400G OSFP single-port adapter ends, carrying InfiniBand NDR or 400 GbE.
Q. Is the 03GX905 the same as NVIDIA MCP7Y00-N01A?
Yes — 03GX905 is Lenovo's option-P/N for the same physical cable NVIDIA ships as MCP7Y00-N01A. Both are 1.5 m passive copper splitters with one finned twin-port 800G OSFP end and two flat single-port 400G OSFP ends. The Lenovo SKU is qualified against Lenovo ThinkSystem platforms.
Q. Is this a 1-to-1 cable or a splitter, and what are the connectors?
It is a hybrid splitter, not a 1-to-1 cable. The switch end is a single twin-port 800G OSFP (finned); the two adapter ends are single-port 400G OSFP (flat). The two OSFP shell variants are physically distinct and cannot be swapped end-for-end.
Q. Will the 03GX905 fit into a QSFP-DD or QSFP112 cage?
No. All three ends are OSFP. OSFP and QSFP-family cages (QSFP+, QSFP28, QSFP56, QSFP-DD, QSFP112) are physically and electrically incompatible. For 1×OSFP → 2×QSFP112 use the MCP7Y10-series instead.
Q. Does the 03GX905 work for HDR (200G) or EDR (100G) InfiniBand?
No, it is an NDR-class cable. NDR uses 100 Gb/s-per-lane PAM4; HDR is 50 Gb/s-per-lane NRZ and EDR is 25 Gb/s-per-lane NRZ. The 03GX905 is characterized for NDR rates only.
Q. What workloads is the 03GX905 designed for?
AI training east-west GPU interconnect (ConnectX-7 / BlueField-3), large-scale HPC compute fabrics, and 400 GbE storage targets over Spectrum-X. The splitter form doubles the radix of an 800G OSFP switch port when feeding two 400G hosts.
Q. Can I deploy this 1.5 m cable between two adjacent racks?
No. At 1.5 m the cable is intra-rack only — typically ToR-to-server or ToR-to-DPU within the same rack. For adjacent-rack or EoR/MoR reach use a longer DAC (3–7 m) or an AOC / optical transceiver pair.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
This unit ships Refurbished Grade A. It is bench-tested by T.E.S IT-SOLUTIONS with link establishment on an NDR-capable test rig where topology allows, EEPROM / vendor-data readout, and cosmetic inspection. Ships from EU stock in professional anti-static packaging with global B2B logistics.

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 since 2007. Every cable is identified by MPN, vendor reference P/N, and connector variant before it ships — finned versus flat OSFP, twin-port versus single-port, NDR versus HDR — so the unit you receive matches the cage on your switch and adapter. Free pre-sale compatibility advice on Quantum-2 / Spectrum-X port-mode and ConnectX-7 / BlueField-3 pairing. Multi-currency B2B invoicing, EU stock with worldwide express, direct engineering contact — not a call-center.