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NVIDIA NVSwitch#

NVIDIA NVSwitch provides a high-bandwidth, low-latency interconnect fabric that enables direct communication between multiple GPUs within a system. NVIDIA NVSwitch enables peer-to-peer vGPU communication within a single node over the NVLink fabric. The NVSwitch acts as a high-speed crossbar that allows any GPU to communicate with any other GPU at full NVLink speed. This design improves communication efficiency and bandwidth compared to traditional PCIe-based interconnections. It facilitates the creation of large GPU clusters, enabling AI and deep learning applications to efficiently use pooled GPU memory and compute resources for complex, computationally intensive tasks. It is supported only on a subset of hardware platforms, vGPUs, hypervisor software releases, and guest OS releases.

For information about using the NVSwitch, refer to the NVIDIA Fabric Manager documentation. On HGX hosts, install and start Fabric Manager before creating multi-GPU VMs - see Installing NVIDIA Fabric Manager on HGX Servers.

Platform Support for NVIDIA NVSwitch#

Table 141 Platform Support for NVIDIA NVSwitch#

Supported Baseboard

NVIDIA HGX B200 8-GPU baseboard

NVIDIA HGX H200 8-GPU baseboard

NVIDIA HGX H100 8-GPU baseboard

NVIDIA HGX H800 8-GPU baseboard

NVIDIA HGX A100 8-GPU baseboard

NVIDIA NVSwitch Limitations#

  • Only time-sliced vGPUs are supported. MIG-backed vGPUs are not supported.

  • All vGPUs communicating peer-to-peer must be assigned to the same VM.

  • On GPUs based on the NVIDIA Hopper and Blackwell GPU architectures, multicast is supported when unified memory (UVM) is enabled.

  • GPU passthrough on NVIDIA systems that include NVSwitch when using VMware vSphere is supported only as a full-node passthrough configuration. Sub-node passthrough configurations, such as 1-, 2-GPU VMs are not supported on NVIDIA HGX systems with VMware vSphere.

Hypervisor Platform Support for NVSwitch#

Consult the documentation from your hypervisor vendor for information about which generic Linux with KVM hypervisor software releases supports NVIDIA NVSwitch.

  • All supported Red Hat Enterprise Linux KVM and Ubuntu KVM releases support NVIDIA NVSwitch.

  • The earliest VMware vSphere Hypervisor (ESXi) release that supports NVIDIA NVSwitch depends on the GPU architecture.

Caution

NVIDIA NVSwitch is not supported on VMware vSphere Hypervisor (ESXi) for NVIDIA Blackwell GPUs.

Table 142 VMware vSphere Releases that Support NVIDIA NVSwitch#

GPU Architecture

Earliest Supported VMware vSphere Hypervisor (ESXi) Release

NVIDIA Blackwell

Not supported on VMware

NVIDIA Hopper

VMware vSphere Hypervisor (ESXi) 8 update 2

NVIDIA Ampere

VMware vSphere Hypervisor (ESXi) 8 update 1

vGPU Support for NVSwitch#

Only the following vGPU for Compute time-sliced vGPUs allocated all of the physical GPU’s framebuffer are supported:

Table 143 vGPU for Compute Support for NVSwitch#

Supported GPU

NVIDIA A800

NVIDIA A100 HGX

NVIDIA B200 HGX

NVIDIA H800

NVIDIA H200 HGX

NVIDIA H100 SXM5

NVIDIA H20
Table 144 NVIDIA NVSwitch Support on the NVIDIA Blackwell GPU Architecture#

Board

vGPU

NVIDIA B200 HGX 180GB

B200X-180C
Table 145 NVIDIA NVSwitch Support on the NVIDIA Hopper GPU Architecture#

Board

vGPU

NVIDIA H800 SXM5 80GB

H800XM-80C

NVIDIA H200 SXM5 141GB

H200X-141C

NVIDIA H100 SXM5 80GB

H100XM-80C

NVIDIA H20 SXM5 141GB

H20X-141C

NVIDIA H20 SXM5 96GB

H20-96C
Table 146 NVIDIA NVSwitch Support on the NVIDIA Ampere GPU Architecture#

Board

vGPU

NVIDIA A800 HGX 80GB

A800DX-80C

NVIDIA A100 HGX 80GB

A100DX-80C

NVIDIA A100 HGX 40GB

A100X-40C

Guest OS Releases Support for NVSwitch#

Linux only. NVIDIA NVSwitch is not supported on Windows. For broader Windows guest limits, refer to Microsoft Windows Server limitations.