NVIDIA 800G OSFP Transceivers Decoded: MMS4X00-NM vs NS, MMA4Z00, Finned vs Flat-Top
NVIDIA's 800G OSFP optics for Quantum-2 InfiniBand and Spectrum-4 Ethernet ship under a handful of part numbers that look almost identical — MMS4X00-NM, MMS4X00-NS, MMA4Z00-NS, plus -FLT, -T and -NS400 variants. Order the wrong one and it either will not fit the cage, will not reach the far end of the hall, or costs you twice what the link actually needed. Here is the decoder.
Rule 1: MMS = single-mode, MMA = multimode
The prefix tells you the fiber plant. MMS4X00 parts are parallel single-mode (DR), 1310nm, running over SMF. MMA4Z00 parts are multimode (SR), 850nm, running over OM3/OM4. They are not interchangeable — the fiber itself is different, so this is the first thing to pin down before anyone quotes you.
Rule 2: NM vs NS is reach, and nothing else
Within the single-mode family, the suffix is purely about distance. Per NVIDIA's own documentation, the 500m MMS4X00-NM and the 100m MMS4X00-NS are the same twin-port 2xDR4 transceiver; the NM part is simply qualified over the longer distance and may use a different FEC scheme.
| Part number | Fiber | Ports | Data rate | Max reach | Typical use |
|---|---|---|---|---|---|
| MMS4X00-NM | SMF 1310nm (DR8) | Twin-port 2x400G | 800Gb/s | 500 m | Switch-to-switch, spine/leaf across a hall |
| MMS4X00-NS | SMF 1310nm (DR8) | Twin-port 2x400G | 800Gb/s | 100 m | Switch-to-switch, in-row |
| MMS4X00-NS400 | SMF 1310nm (DR4) | Single-port | 400Gb/s | 100 m | ConnectX-7 / BlueField-3 host side |
| MMA4Z00-NS | MMF 850nm (SR8) | Twin-port 2x400G | 800Gb/s | 50 m | Short in-hall links |
| MMA4Z00-NS400 | MMF 850nm (SR4) | Single-port | 400Gb/s | 50 m | Host side, short reach |
The practical consequence: if every link in your fabric is inside 100 meters, the NS part does the same job for less money. NM is the part you need the moment a cable run crosses halls or floors. NM will of course also work on short runs — it is the safe over-spec, just not the cheap one.
Rule 3: twin-port feeds two host ports
The twin-port design is the reason a 32-cage Quantum-2 switch presents 64 ports of 400Gb/s. One 800G twin-port module on the switch fans out into two 400G single-port modules (the -NS400 class) on the ConnectX-7 or BlueField-3 side. When you build a BOM, count switch-side and host-side optics separately — they are different part numbers at roughly a 1:2 ratio, not the same SKU twice.
Rule 4: finned vs flat-top is not cosmetic
Quantum-2 and Spectrum-4 switches require the finned-top OSFP shell for extra cooling — that is the base part number. The flat-top -FLT variant exists for systems such as DGX H100 whose cages do not need it. A flat-top module in a switch cage is a thermal problem; a finned module often will not seat in a host cage at all. Confirm the housing on every line of the quote.
Rule 5: the -T suffix
NVIDIA publishes separate product pages for -T variants (MMS4X00-NM-T, MMS4X00-NS-T, MMA4Z00-NS-T, MMA4Z00-NS400-T). Optically they match their base part; they are ordered as distinct SKUs, so quote against the exact string on the customer's BOM rather than normalising it away.
A five-question checklist before you buy
- Single-mode or multimode? Existing fiber plant decides this — MMS vs MMA.
- Longest link in the fabric? Under 50 m opens up MMA; under 100 m means NS; beyond that you need NM.
- Switch side or host side? Twin-port 800G vs single-port 400G, roughly 1:2.
- Which chassis? Quantum-2 / Spectrum-4 need finned; DGX-class cages take -FLT.
- Exact SKU string, including any
-Tor-FLTsuffix.
Sourcing these parts
Scaling Trade stocks and sources the full NVIDIA 800G/400G OSFP optics line — MMS4X00 and MMA4Z00 families, finned and flat-top, in both InfiniBand and Ethernet configurations — alongside Quantum-2 switches, ConnectX-7 and BlueField-3 adapters. Send us the port count and the longest link length and we will come back with the right part numbers and current pricing, not just a catalogue dump.