Hi,
v4 is based on CUDA 10, so you need 2020.2-XB5 based on CUDA 11.1, to have the full RTX 30X0 support:
viewtopic.php?f=33&t=76196
You also need to upgrade the Nvidia driver to 456.38 or greater, with a clean installation.
There is also a a new cuDNN library that needs to be installed at first start:
ciao Beppe