
DeepSpeed
DeepSpeed, powered by Zero Redundancy Optimizer (ZeRO), is an optimization library for training and fitting very large models onto a GPU. It is available in several ZeRO stages, where each stage progressively saves more GPU memory by partitioning the optimizer state, gradients, parameters, and enabling offloading to a CPU or NVMe. DeepSpeed is integrated with the [Trainer] class and most of the setup is automatically taken care of for you. 
However, if you want to use DeepSpeed without the [Trainer], Transformers provides a [HfDeepSpeedConfig] class.