CNTK

Microsoft's open-source deep learning library built for high-performance distributed training across massive datasets.

CNTK (Microsoft Cognitive Toolkit) treats neural networks as a series of computational steps via a directed graph. Microsoft engineered this framework to scale across multiple GPUs and machines: it powered the production models for Skype, Cortana, and Bing. It supports Python, C++, and C# APIs while maintaining a reputation for speed in recurrent neural network (RNN) training. Although the project reached its final release (v2.7) in 2019, it remains a reference point for efficient memory usage and distributed performance on large-scale datasets.

https://github.com/microsoft/CNTK