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The 800G OSFP SR8 and 800G OSFP RHS transceivers are identical in electrical performance, transmission rate, and internal circuitry (both 8x100G PAM4). The fundamental difference lies in their physical packaging structure (thermal design) and the types of switch ports they support. In below article, we will conduct a comparative analysis one by one.
Heat dissipation design (core difference)
OSFP SR8 (Standard Edition):
- Comes with heat sink: The top of the OSFP transceiver housing has obvious heat sink fins.
- Principle: The transceiver’s heat dissipation mainly relies on its built-in fins, which move along with the module during insertion and removal. This design has extremely high heat dissipation efficiency and is suitable for ultra-high power consumption environments.
OSFP-RHS (Flat / Riding Heat Sink)：
External heat sink: The surface of the module is flat without fins.
- Principle: Heat dissipation relies on the built-in heat sink on the switch slot. When the module is inserted, the heat sink of the switch will tightly adhere to the surface of the module.
- Advantages: Lower height, allowing for higher port density.
Physical dimensions and appearance
- OSFP Transceiver: Due to its built-in heat dissipation fins, the module as a whole appears very “thick” or “high”.
- OSFP-RHS Transceiver: It looks like a “flat” OSFP transceiver.
Switch compatibility (determines which one you buy)
These two types of packaging are usually not interchangeable, depending on the design of the switch manufacturer:
NVIDIA (Mellanox) switches:
Quantum-2 (IB)(MQM9700/9790) and Spectrum-4 (Ethernet) switches typically use OSFP-RHS ports, as the switch cage already integrates large heat sinks.
Other vendors (such as Arista, Cisco):
Many tend to use standard OSFP (modules with built-in fins) to simplify the structural design of switch chassis.
Comparison Table of Key Parameters
| feature | 800G OSFP SR8 | 800G OSFP-RHS SR8 |
| heat sink | Integrated on modules | Provided by the switch (flat module) |
| Single channel speed | 100G PAM4 (8 channels) | 100G PAM4 (8 channels) |
| interface type | MPO-12/APC | MPO-12/APC |
| maximum distance | 100m (OM4) | 100m (OM4) |
| Typical Applications | Universal high-performance switch | NVIDIA H100 Cluster Switch |
Selection suggestions
- Check the switch slot: Observe the inside of the switch port. If you see a row of aluminum or copper heat dissipation teeth above the port, then you need to buy OSFP-RHS transceiver; If the port is just a hole, you need to buy a standard OSFP transceiver with built-in heat sink.
- Confirm the network card end: NVIDIA H100 and other 800G network cards usually use OSFP (with fins), but due to the fact that the network card only has 1-2 ports, the heat dissipation pressure is relatively dispersed.
Conclusion
If bought the wrong module, the transceiver may not fit in the switch physically, or the module may overheat and shut down instantly due to the heat sink not fitting properly after insertion. So please follow the advice given by Yingda above and purchase with caution.
FAQ
Do Huawei switches use OSFP or OSFP-RHS transceiver?
Huawei switches do not only use one type, but are flexibly configured according to product positioning:
- For ordinary enterprise level applications, mature SFP/QSFP series packaging is still the main choice.
- Pursuing high performance and future readiness: Choose high-end core switches with native OSFP packaging.
- Pursuing ultra-high density and port quantity: Choose expansion cards or specific models that support OSFP-RHS modules.
What is the power consumption of OSFP transceiver?
The maximum 800G optical transceiver power consumption of the OSFP SR8 provided by Yingda is 14 watts.
What is the power consumption of OSFP-RHS transceiver?
The maximum power consumption of the OSFP-RHS SR8 optical module provided by Yingda is 14W. The power consumption of ZR/Zr+optical module is as high as 30W.
What other 800G pluggable optics can Yingda provide besides the 800G SR8 module?
In addition to the 800G OSFP SR8 transceiver, Innolux can also provide 800g OSFP DR8, 800g OSFP 2xDR4800g OSFP 2xFR4, as well as QSFP packaged optical modules, such as qsfp dd800 dr4, qsfp 800g dr4,qsfp 800g dr8,qsfp 800g vr8,qsfp dd800 8x100g lr1. High speed cables such as 800g OSFP DAC and 800g OSFP AEC can also be provided.