@ptrblck  I have SSD, I’m on Windows (I know…), reading hdf5 file is very fast, when I feed it, either, to the map or iterable dataset class, then to the data loader, and then iter-ating it, it’s very slow, then next() calls are all equally very slow too…
Note: For what its worth, running some torchvison.dataset, i.e. MNIST from pytorch *.pt file, it runs pretty fast.