xGMI (inter-chip global memory interconnect) is a cable-capable version of AMD's Infinity Fabric interconnect. A line of code in the latest version of AMDGPU Linux drivers reveals that "Vega 20" will support xGMI. This line tells the driver to check the state of xGMI link. A practical implementation of this could be inter-card high-bandwidth bridge connectivity that would otherwise saturate the PCI-Express host bus; similar to NVIDIA's usage of the new NVLink bridge for Quadro and Tesla products based on its "Volta" and "Turing" GPU architectures.

By no means should xGMI and NVLink implementations be interpreted as a coming back of multi-GPU to the gaming space. There are still no takers for DirectX 12 multi-GPU, and fewer AAA games support SLI or CrossFire. Even at higher resolutions/refresh-rates, existing SLI/CrossFire physical-layer standards have sufficient bandwidth for multi-GPU. The upcoming GeForce RTX 2000 graphics cards feature a new multi-GPU connector that's physically NVLink, but this is probably an attempt by NVIDIA to discard the legacy SLI bus and minimize redundant interfaces on its silicon. The TU102 and TU104 chips are implemented in the enterprise segment with the Quadro RTX family. The main application of xGMI/NVLink is to make multi-GPU hardware setups abstract to deep-learning software, so hardware can scale in the background with memory access spanning multiple GPUs. "Vega 20" will be launched in Radeon Pro and Radeon Instinct avatars late-2018.