NVIDIA MMA4Z00-NS400 / 980-9I51S-00NS00 Compatible 400G OSFP SR4 Flat-Top (RHS) Transceiver — MPO-12/APC, 850nm MMF, for ConnectX-7
Warranty: Lifetime
Flat-Top (RHS) — the NIC-side module, not the switch-side module
NVIDIA MMA4Z00-NS400 / 980-9I51S-00NS00 compatible — 400G OSFP SR4, 850nm multimode
→ NVIDIA OSFP part-number crosswalk — Mellanox MMA/MMS numbers mapped to the new NVIDIA 980- numbers, with form factor, optics and the correct part for each end of the link.
Mellanox Part Number: MMA4Z00-NS400
NVIDIA Part Number: 980-9I51S-00NS00
Description: Single-port OSFP SR4 optical transceiver, 400Gb/s, flat-top / Riding Heat Sink (RHS), MPO-12/APC, multimode
This is the flat-top module — the one that goes in the server, not the switch. If you are populating an OSFP port on a ConnectX-7 or ConnectX-8 adapter, a BlueField-3 DPU, or a DGX system, this is the correct part. Those ports carry their own heatsink built into the port cage, and it rides down on top of whatever module you insert. A finned module has no clearance underneath it and will not seat.
NVIDIA now calls this form factor RHS, for Riding Heat Sink — the equipment's heatsink rides on the module. Older documentation, existing BOMs and most purchase histories still say "flat-top." Same part.
Which One Do I Need?
| Going into | You need |
|---|---|
| ConnectX-7 / ConnectX-8 NIC, BlueField-3 DPU, DGX system | Flat-Top (RHS) — this product |
| Air-cooled Quantum-2 switch (QM9700 / QM9790) | Finned-Top (IHS) — 800G twin-port module |
The fins are either on the module or on the equipment. Never both, never neither.
The two parts are designed as a pair: one twin-port finned module in the switch → two MPO-12/APC patch cords → two flat-top modules in two ConnectX-7 servers. One switch module serves two servers.
Technical Specifications
| Specification | Value |
|---|---|
| Mellanox Part Number | MMA4Z00-NS400 |
| NVIDIA Part Number | 980-9I51S-00NS00 |
| Form Factor | Single-port OSFP, Flat-Top (Riding Heat Sink / RHS) |
| Data Rate | 400Gb/s — 4 x 106.125Gb/s PAM4 |
| Optical Interface | SR4, 850nm, multimode (MMF) |
| Connector | MPO/MTP-12 APC |
| Reach | 30m OM3 / 50m OM4 — see note below |
| Protocol | InfiniBand NDR and 400G Ethernet |
| Host Platforms | ConnectX-7 and ConnectX-8 OSFP adapters, BlueField-3 DPUs, DGX systems |
| DOM / DDM | Supported |
| Coding | Coded specifically for NVIDIA / Mellanox |
| Standards | OSFP MSA, IEEE 802.3ck, Class 1 laser, RoHS |
| Warranty | Lifetime, backed by Resilient Tec |
| Condition | New |
Note on Reach: Why You'll See Both 50m and 100m
NVIDIA specifies 50m over OM4 for this module, and that is the figure to design against in an InfiniBand fabric. The optics are built to the SR MSA, which permits up to 100m over OM4 — so both numbers are correct, they just answer different questions. The standard describes what the optics can do under ideal conditions; NVIDIA's number is what they will support.
Usable reach past 50m depends on fiber grade and how many MPO matings sit in the path, because every additional mating costs optical budget. A 90m run through three patch panels is exactly where link margin quietly disappears. Design to 50m for NVIDIA support parity. Planning a longer run? Talk to us first.
Good to Know
- A finned-top (IHS) module will not physically seat in a ConnectX-7 OSFP port — the cage heatsink is in the way. This is the most common wrong order on this part.
- 800G is not an upgrade at the server end: the ConnectX-7 OSFP port is a 400G port.
- MMA1Z00-NS400 is one character away and is QSFP112 — a different cage entirely. It will not fit an OSFP port.
- MMS4X00-NS400 is single-mode DR4 at 1310nm, 500m. The MMA / MMS prefix is the tell: MMA is multimode, MMS is single-mode.
- Running single-mode? This is not your module. Tell us what the fiber plant is and we will point you at the right part rather than sell you this one.
- Liquid-cooled switch deployments need the 800G flat-top variant (MMA4Z00-NS-FLT), which we do not stock. We will still tell you what to look for.
Quick Checklist — Is This the Right Module?
You are populating an OSFP port on a ConnectX-7 or ConnectX-8 adapter, a BlueField-3 DPU, or a DGX system. The port cage has its own heatsink. Your fiber plant is multimode (OM3 or OM4) with MPO-12/APC connectors. Your runs are 50m or shorter. You want 400G NDR InfiniBand or 400G Ethernet.
Availability
In stock: 1 · Additional units ship on a 7–10 day lead time.
Building a cluster? Tell us how many ports you are populating and we will quote the switch-side and server-side modules together. Request a quote →
Warranty: lifetime, backed by Resilient Tec — not a manufacturer term. When a module fails you reach a named seller in Knoxville, Tennessee, not a ticket queue.
You Might Also Need
- 800G OSFP SR8 Finned-Top (IHS) twin-port transceiver — the switch-side half of the link. One of those serves two of these.
- MPO-12/APC multimode patch cords, Type B polarity — the fiber between the two modules
- OSFP DAC cables — when the run is short enough that copper beats optics
- Product guides — structured cabling, switches and the rest of the rack
Related Guides
Flat-Top or Finned-Top OSFP? How to Tell Which Module Your ConnectX-7 Actually Needs
NVIDIA OSFP Part-Number Crosswalk: Mellanox MMA/MMS to NVIDIA 980- Numbers
Flat-Top (RHS) — the NIC-side module, not the switch-side module
NVIDIA MMA4Z00-NS400 / 980-9I51S-00NS00 compatible — 400G OSFP SR4, 850nm multimode
→ NVIDIA OSFP part-number crosswalk — Mellanox MMA/MMS numbers mapped to the new NVIDIA 980- numbers, with form factor, optics and the correct part for each end of the link.
Mellanox Part Number: MMA4Z00-NS400
NVIDIA Part Number: 980-9I51S-00NS00
Description: Single-port OSFP SR4 optical transceiver, 400Gb/s, flat-top / Riding Heat Sink (RHS), MPO-12/APC, multimode
This is the flat-top module — the one that goes in the server, not the switch. If you are populating an OSFP port on a ConnectX-7 or ConnectX-8 adapter, a BlueField-3 DPU, or a DGX system, this is the correct part. Those ports carry their own heatsink built into the port cage, and it rides down on top of whatever module you insert. A finned module has no clearance underneath it and will not seat.
NVIDIA now calls this form factor RHS, for Riding Heat Sink — the equipment's heatsink rides on the module. Older documentation, existing BOMs and most purchase histories still say "flat-top." Same part.
Which One Do I Need?
| Going into | You need |
|---|---|
| ConnectX-7 / ConnectX-8 NIC, BlueField-3 DPU, DGX system | Flat-Top (RHS) — this product |
| Air-cooled Quantum-2 switch (QM9700 / QM9790) | Finned-Top (IHS) — 800G twin-port module |
The fins are either on the module or on the equipment. Never both, never neither.
The two parts are designed as a pair: one twin-port finned module in the switch → two MPO-12/APC patch cords → two flat-top modules in two ConnectX-7 servers. One switch module serves two servers.
Technical Specifications
| Specification | Value |
|---|---|
| Mellanox Part Number | MMA4Z00-NS400 |
| NVIDIA Part Number | 980-9I51S-00NS00 |
| Form Factor | Single-port OSFP, Flat-Top (Riding Heat Sink / RHS) |
| Data Rate | 400Gb/s — 4 x 106.125Gb/s PAM4 |
| Optical Interface | SR4, 850nm, multimode (MMF) |
| Connector | MPO/MTP-12 APC |
| Reach | 30m OM3 / 50m OM4 — see note below |
| Protocol | InfiniBand NDR and 400G Ethernet |
| Host Platforms | ConnectX-7 and ConnectX-8 OSFP adapters, BlueField-3 DPUs, DGX systems |
| DOM / DDM | Supported |
| Coding | Coded specifically for NVIDIA / Mellanox |
| Standards | OSFP MSA, IEEE 802.3ck, Class 1 laser, RoHS |
| Warranty | Lifetime, backed by Resilient Tec |
| Condition | New |
Note on Reach: Why You'll See Both 50m and 100m
NVIDIA specifies 50m over OM4 for this module, and that is the figure to design against in an InfiniBand fabric. The optics are built to the SR MSA, which permits up to 100m over OM4 — so both numbers are correct, they just answer different questions. The standard describes what the optics can do under ideal conditions; NVIDIA's number is what they will support.
Usable reach past 50m depends on fiber grade and how many MPO matings sit in the path, because every additional mating costs optical budget. A 90m run through three patch panels is exactly where link margin quietly disappears. Design to 50m for NVIDIA support parity. Planning a longer run? Talk to us first.
Good to Know
- A finned-top (IHS) module will not physically seat in a ConnectX-7 OSFP port — the cage heatsink is in the way. This is the most common wrong order on this part.
- 800G is not an upgrade at the server end: the ConnectX-7 OSFP port is a 400G port.
- MMA1Z00-NS400 is one character away and is QSFP112 — a different cage entirely. It will not fit an OSFP port.
- MMS4X00-NS400 is single-mode DR4 at 1310nm, 500m. The MMA / MMS prefix is the tell: MMA is multimode, MMS is single-mode.
- Running single-mode? This is not your module. Tell us what the fiber plant is and we will point you at the right part rather than sell you this one.
- Liquid-cooled switch deployments need the 800G flat-top variant (MMA4Z00-NS-FLT), which we do not stock. We will still tell you what to look for.
Quick Checklist — Is This the Right Module?
You are populating an OSFP port on a ConnectX-7 or ConnectX-8 adapter, a BlueField-3 DPU, or a DGX system. The port cage has its own heatsink. Your fiber plant is multimode (OM3 or OM4) with MPO-12/APC connectors. Your runs are 50m or shorter. You want 400G NDR InfiniBand or 400G Ethernet.
Availability
In stock: 1 · Additional units ship on a 7–10 day lead time.
Building a cluster? Tell us how many ports you are populating and we will quote the switch-side and server-side modules together. Request a quote →
Warranty: lifetime, backed by Resilient Tec — not a manufacturer term. When a module fails you reach a named seller in Knoxville, Tennessee, not a ticket queue.
You Might Also Need
- 800G OSFP SR8 Finned-Top (IHS) twin-port transceiver — the switch-side half of the link. One of those serves two of these.
- MPO-12/APC multimode patch cords, Type B polarity — the fiber between the two modules
- OSFP DAC cables — when the run is short enough that copper beats optics
- Product guides — structured cabling, switches and the rest of the rack
Related Guides
Flat-Top or Finned-Top OSFP? How to Tell Which Module Your ConnectX-7 Actually Needs
NVIDIA OSFP Part-Number Crosswalk: Mellanox MMA/MMS to NVIDIA 980- Numbers