Hi ptrblck,
I have encountered a similar problem a few days ago.
The utilization of GPU sometimes high  to 80% and sometimes low to 20% in the traing phase, and the utilization is close to zero in validation phase.
After I try different num_workers  value in dataloader and compute metircs on GPU instead on CPU in numpy, the utilization can be 80-90% stably, but in validation phase at the end of each epoch, the utilization is still close to 0, what might make this strange phenomenon?
Thanks in advance:thinking: