I have an external Western Digital HDD (1gig) which is running very slow, 0.5 - 1mb per second. This is on a Mac Pro running the latest OS with all the patches. The HDD is connected via USB directly to the computer (i.e. no hub or anything.) Also I ran a disk diagnostic on it which comes up clean. The deeper diagnostic takes too long to finish.could it be a hardware problem in the HDD?could I need a different cable?any other diagnostic steps that you might suggest?Additional info I got from the OS. Does that tell you anything (me not)ext HDD 1021:  Product ID:   0x1021  Vendor ID:    0x1058  (Western Digital Technologies, Inc.)  Version:  20.21  Serial Number:    888881563550353537363230  Speed:    Up to 480 Mb/sec  Manufacturer: Western Digital  Location ID:  0xfa200000 / 2  Current Available (mA):   500  Current Required (mA):    2  Capacity: 1 TB (1,000,202,043,392 bytes)  Removable Media:  Yes  Detachable Drive: Yes  BSD Name: disk2  Partition Map Type:   GPT (GUID Partition Table)  S.M.A.R.T. status:    Not Supported  Volumes:EFI:  Capacity: 209.7 MB (209,715,200 bytes)  BSD Name: disk2s1  Content:  EFIExternalHD:  Capacity: 999.86 GB (999,858,069,504 bytes)  File System:  HFS+  BSD Name: disk2s2  Content:  Apple_HFS  Volume UUID:  FFFFFEB2-42F8-3510-85F4-12632D99D19B
Why might an external Hard Disk Run super slow?
osx;hard disk