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Hardware & Systems

3D Parallelism

Training a huge model by splitting the work three ways at once — across data, across layers, and within layers — over many GPUs.

Definition

3D parallelism is the strategy used to train the largest models by combining three ways of splitting the work across many GPUs at the same time: data parallelism (different GPUs process different examples), pipeline parallelism (different GPUs handle different layers), and tensor parallelism (a single layer's math is split across GPUs). Each dimension handles a different bottleneck, and together they let a model far too large for any one machine train efficiently across thousands of chips. Coordinating all three is complex, which is why it is mostly used at frontier scale.