Pytorch image normalization is very slow in total code and my computer. But if only run normalization code is fast normally in my computer . My friend computer i9 9700K cpu and 2080 gpu. torch image normalization is very fast more than 25 times me in total code. My computer i7 9700K 2070 nvidia. Our code (torch.cuda.floattensor(image)/255-0.5)/0.5