ModelExpress (MX) is a weight distribution and cache management service within the NVIDIA Dynamo system. Its core innovation is that inference nodes no longer rely on a central server to broadcast weights; instead, they fetch updated weights directly from other GPUs via NIXL. This GPU-to-GPU RDMA path avoids the bottleneck of centralized broadcast, while MX reuses kernel caches to further reduce redundant loading.
NVIDIA emphasizes "removing weight movement from the critical path," meaning that in the traditional startup process, the weight loading from storage to GPU is a major source of latency. By using GPU direct RDMA, weight transfer can partially overlap with computation, significantly shortening startup time.
This architecture is applicable not only to startup but also to inference and reinforcement learning post-training, indicating that weight movement path optimization is a cross-scenario general performance improvement technique.