I did a small benchmark script to time the noise creation for PyTorch vs TensorFlow.
Noise size = (1024, 128, 128) -
PyTorch Time = 0.09 Sec
TF Time= 0.03 Sec
Noise size = (1024, 256, 256) -
PyTorch Time =  0.398 Sec
TF Time= 0.118 Sec
Since noise sampling torch.randn or normal_dist.sample happens on CPU, then we move the results to GPU. So I measured the time of generation of random noise without actually moving them to GPU.