Hi,
thanks for your response 
I printed the tensors and they’re on the GPU (device=cuda0).
I also tried increasing the batch size to 32 and 64 and still nothing…
what about the alarming signs from nvidia-smi, such as the “N/A” in the GPU memory usage for the process, or this:
Processes
    Process ID                  : 15980
        Type                    : C
        Name                    : C:\Users\itaim\AppData\Local\Programs\Python\Python36\python.exe
        Used GPU Memory         : Not available in WDDM driver model

what is this WDDM?
Thanks,
Itai