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I'm experiencing a strange issue with one of my SATA HDDs. Basically I have two internal HDDs that I am connecting to the PC through a SATA-to-USB adapter. I am not keeping them inside the PC since they are only used for backups.
Anyway, one of these HDDs has a strange issue such that when I copy large amounts of data - single large file OR multiple small files - of over 1GB, the copy process slows down dramatically. The average transfer rate is of 30MB/s and works well if the copy operation does not exceed ~700MB.
If the write operation is large, after ~30 seconds, the estimated transfer speed starts dropping down until it eventually reaches ~2MB/s!
I have re-formatted the drive a number of times with FAT / NTFS and different block sizes. I have also toggled the Windows caching option with no effect. I have run Windows CheckDisk as well as various tests from HDDScan and both had no issues to report. S.M.A.R.T statistics also seems OK.
The other HDD runs smoothly with a constant ~30MB/s transfer rate (using the same adapter).
Anyone has any idea what the issue might be? Thanks!
user39239
Posted 2014-03-25T13:49:29.930
Reputation: 21
1A section of the drive very well might be damaged, have you attempted to run any diagnostics using the manufacturer's diagnostic software? The other possibility is the cache on one of those drives is smaller so there is a bottleneck in how much data it can write to the drive any given time. – Daniel Chateau – 2014-03-25T14:03:27.780
@DanielChateau - No, I haven't tried running the manufacturer's diagnostic software. The manufacturer is Samsung, but I will try it out and see if this results in anything. – user39239 – 2014-03-25T14:06:47.787
possible duplicate of Weird HDD Slowdown Issue
– qroberts – 2014-03-25T14:07:45.6172@qroberts - Yes that is my own question. Sorry, was not aware that the other question will be migrated to SuperUser. Apologies. – user39239 – 2014-03-25T14:12:02.993
Have you tried a different USB port, e.g. swapping the two drives? You might have a USB problem, not a HDD problem – Eugen Rieck – 2014-03-25T14:17:27.343
@EugenRieck - As I mentioned in my question, I have tried the other HDD, and I have also tried different USB ports - and the other disk works well in both combinations. So I'm guessing the USB is out of the question. – user39239 – 2014-03-25T14:19:39.210
The drive is broken, or the cable or the cable "jack"! – Dave – 2014-03-25T14:51:31.150
If the same adapter and the same cable perform differently on two differrent hdds then the problem is the hdds. – Ramhound – 2014-03-25T15:37:02.190
@Ramhound - I'm actually quite certain that something is wrong with the HDD, but I don't know what might be wrong with it since checkdisk S.M.A.R.T. statistics and other tests haven't revealed anything yet, although I haven't tried manufacturer diagnostics yet... – user39239 – 2014-03-25T15:43:54.877
@user39239 - S.M.A.R.T only detects certain types of things. If there is a mechanical failure that is not detected by the tests then you are out of luck. – Ramhound – 2014-03-25T15:53:54.753
1@DanielChateau - Following your advice, yesterday I downloaded the SeaTools application, and after several lengthy checks (which resulted in nothing), I tried the MBR erase from the tool, and that seems to have solved the problem actually!!! I wrote a few large files on the disk and they copied at a steady ~30MB/s although I will try filling up the whole disk now to ensure that the speed remains stable and no corruption occurs :) – user39239 – 2014-03-26T08:31:27.953