NVLink

NVLink is NVIDIA's proprietary high-speed interconnect that links GPUs to each other (and to NVIDIA CPUs) at far higher bandwidth than PCIe, letting multiple GPUs pool memory and act as one large accelerator. Fifth-generation NVLink on Blackwell GPUs provides 1.8 TB/s of bidirectional bandwidth per GPU — roughly 14 times PCIe Gen5 — and NVLink Switch chips extend this into rack-scale fabrics: the GB200 NVL72 connects 72 GPUs in one 120-130 kW liquid-cooled rack with 130 TB/s of aggregate NVLink bandwidth. Within the NVLink domain, GPUs share memory coherently, which is critical for training and serving trillion-parameter models. Beyond the rack, clusters fall back to InfiniBand or Ethernet. NVLink Fusion, announced in 2025, opens the fabric to select third-party CPUs and accelerators.