# Dataloader SuperSuper Slow **URL:** \ **Category:** vision\ **Created:** [February 4, 2020, 1:29am UTC](https://discuss.pytorch.org/t/dataloader-supersuper-slow/68563 "2020-02-04T01:29:01Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![ptrblck](https://discuss.pytorch.org/user_avatar/discuss.pytorch.org/ptrblck/32/1823_2.png) [@ptrblck](https://discuss.pytorch.org/u/ptrblck)\ **Post date:** [February 4, 2020, 5:12am UTC](https://discuss.pytorch.org/t/dataloader-supersuper-slow/68563/2 "2020-02-04T05:12:33Z")
Did you measure the data loading time during the training or just the first iteration? Note that the first step will spin up all workers, and each will load a complete batch, which might introduce some warmup time. Also, where is your data stored? Is it on a local SSD or some other hard drive? Have a look at [this post](https://discuss.pytorch.org/t/how-to-prefetch-data-when-processing-with-gpu/548/19) which gives a good summary for potential bottlenecks. --- _[View the full topic](https://discuss.pytorch.org/t/dataloader-supersuper-slow/68563)._