7200rpm external drive significantly slowing down
One of my external hard drives has been slowing down more and more with each plugging in. The drive is 2.5-in. 7200rpm 1TB. I have noticed that it takes longer to mount the drive and lately longer and longer to show its content. The same problem appeared after I placed the drive in a different enclosure. As I am writing I have the drive hooked up to the 5K iMac that belongs to my friend, connecting via USB3.0. The drive is slightly over 50% filled. But about a month ago it was almost full, down to just under 2GB free space.
Transferring a small file is relatively fast, but to transfer 5GB of files would take more than 20 minutes.
I suspect that there are bad sectors or something else is not working right. Is the drive dying and this could be its last mounting? I have the drive hooked up to the 5K iMac until all the files are transferred over.