This post details the performance gains achieved by CoreWeave's new NVIDIA GB300 NVL72 instances, featuring NVIDIA Blackwell Ultra GPUs, when running the DeepSeek R1 reasoning model. It quantifies a 6.5x performance improvement on inference compared to a 16-GPU NVIDIA H100 system, attributing this to the GB300's superior memory and interconnect bandwidth, which allows for 4-way Tensor Parallelism (TP4) versus TP16 on H100, significantly reducing communication overhead. The post also elaborates on the GB300 NVL72 architecture, including its 37TB memory, 130TB/s NVLink bandwidth, and integration with NVIDIA Quantum-X800 InfiniBand. CoreWeave's platform-specific optimizations, such as the Rack LifeCycle Controller, topology-aware scheduler leveraging NVLink labels, and observability through Grafana dashboards, are presented as key enablers of this record performance.