Refreshing CNTK with CUDA 11.8 for Ada Lovelace support

This is a quick blog post to announce that I have refreshed the open source Microsoft Cognitive Toolkit (CNTK) library with CUDA 11.8 (and cuDNN in order to get support for NVidia Ada Lovelace/40 series GPUs. Work was completed in the PR Building with Visual Studio 2022 (v143) and CUDA 11.8 and protobuf 3.14.0 via vcpkg and the following things were changed:

  • Update to CUDA 11.8 and cuDNN
  • Update from PlatformToolset v141 to v143 (Visual Studio 2022 MSVC)
  • Support compute_61,sm_61;compute_75,sm_75;compute_80,sm_80;compute_86,sm_86;compute_90,sm_90. That is add Ada Lovelace (RTX 40xx).
  • Use protobuf 3.14.0 via vcpkg.
  • Add protobuf generated code to git.
  • Add Save overload that takes ModelFormat to FunctionShim.cs, to enable saving as onnx from C#.
  • Add zlibwapi.dll to CUDA nuget package since new dependency.
  • Split cublasLt.dll out into separate nuget package since package size otherwise > 512 MB.
  • Disable various warnings to avoid build breaking as those warnings treated as errors. Mostly data conversion warnings.

And fix various code issues. This builds upon the work detailed in Reviving CNTK with CUDA 11.4 for Ampere support with same comments as that. See the release at:

Release 2.9.0

Like last time packages cannot be found on since they are too large, so they have been published to my GitHub packages feed at They can also be downloaded as part of the above release.