You appear to have already done the usual, so accept the results. Even MS is offering a HD is in need of attention and you're finding the 1Tb not all OK. Where does this leads to suspect??? Swap the drive and store the data to yet another HD or what have you, because it seems like it's going South.If you have warranty, then WD will want you to run tests and that may include the "destructive ones" so be prepared.
The other side of this, if you have SMART turned-ON what is it offering? Also, since this HD has been used for various tasks, save the data and simply full format it and hope for the best. I said full format, not the quick format. If it passes that w/o any errors, you may have had some file structure problem or similar prior. However, if the problem comes back after some time, you have some "soft error" of sorts that's popping-up. Again, very probable to just replace the HD as that seems where it's going. You didn't mention how much data is stored on the HD, but if this amount is huge, it may slow down abit as it fetches files, even big ones, it just does for a stuffed drive.
tada -----Willy 
Hey guys,
I have a 1 TB WD Green internal HD that I suspect is having some issues. The hard drive isn't very old, but has been in and out of several PC's and sometimes stored a while inbetween. In my current set-up, I have another 1 TB WD Green that behaves just fine.
The HD feels slow and unresponsive. It's used for storing lots of relatively large video files, typically FRAPS captures. When trying to play any one of these files in e.g. VLC, it stutters and needs lots of time to load in order to play it properly (in VLC a yellow overlay over the time track appears), if it plays anything at all. If I copy one of these files to the other WD Green HD, oddly enough, the file usually will play smoothly from either drive. However, if I leave the computer for a while, maybe also rebooting it, the file will play nicely from the good HD, but poorly from the HD I am having issues with.
Now the odd thing is I downloaded WD's hard drive checking tool, which reported that the drive was perfectly healthy. I had a look at some 3rd party tools for checking HDs, but tbh they were a bit daunting.
On a side note, I have been recieving repeated error notifications in Windows Action Centre saying a hard drive needs to be checked for errors, but it doesn't say which one. Not sure if it is related, but I also did a fsutil dirty check which reported only my system SSD to be dirty. After a chkdsk on the SSD I did a day back, I haven't seen any more disk error messages yet.
Truth be told, I can't remember if these issues have been present ever since I begun using this HD on this system, but I'm leaning towards that they weren't there in the beginning.
Can't remember all my system specs atm, I can check when I get home, but I'm on Windows 8.1 64-bit, on a Asus P6T Deluxe V2 MB.
Any ideas what can be causing this, or how I can solve it?
Thanks!
Tiro
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