I am also facing this issue, 23.65 GB on the card but only 12.53GB reserved by PyTorch. The card is set to exclusive mode.

RuntimeError: CUDA out of memory. Tried to allocate 10.84 GiB (GPU 0; 23.65 GiB total capacity; 1.03 GiB already allocated; 10.26 GiB free; 12.53 GiB reserved in total by PyTorch)

It would be really helpful to understand why this memory is not being utilised