Thanks! In the meanwhile I figured out that it is not the version of cudnn, but that my from source installation didn’t recognize cudnn. torch.backends.cudnn.is_available() is False for all my attempts of in installing torch from source and True for the conda installations.
I installed pytorch from source by creating a new conda environment with python3.8, loading a cuda-11.0.2 module following the steps in the installation instructions I exported CUDA_HOME, CUDNN_LIB_DIR, CUDNN_LIBRARY and CUDNN_INCLUDE before executing “python setup.py install”. The installation works and cuda is available, but cudnn not. Any ideas how to fix it?