Sudden Significant Drop on R/W Speed of Hard Drive

Hello forum,

My PC has a Gigabyte X58A UD3R rev2.0 mobo, i7 950 CPU, GTS450 and 12GB DDR3 RAM. It is running Windows 7 64bit. There are two hard drives, both from WD:
WD10EALS-002BA0 1TB
WD5000AADS-00S9B0 500GB(Windows is on this drive)
*Both drives are 3 years old*

Recently, everything that involves hard drive R/W is slow on the system basically:
-Windows boot up took about 10mins
(no matter normal mode or safe mode)
-Files Moving/Copying/Opening/Deleting
(Avg R/W operation speed is about 1MB/s on both hard drives, sometimes it gets to 700KB/s and lower; This happen to every type of files. I even tried to copy files from one hard drive to another, it turned out that the speed is the same.)
-Application launch
(not so significant speed drop on this one though, but still its slower than before, applications that took 1sec to open now took 5sec)

What I have done:
-I used the HD Tune application to check both drives. And everything is OK(green color), no warnings or errors. Also, the speed is quite normal(About hundred and more MB per sec).
-Head into msconfig and enable only the services by Microsoft, disabled all others. Also disabled all startup things.

Note:
-I did not make any hardware changes to my computer since March
-No drivers or software is installed/removed since March
-Device manager says both drives are operating correctly and it can recognize my drive model names

Even more strange:
From what I saw from my research on the Internet shows that people with such slow HDD speed problems are always seeing their speed drops reflected in disk testing applications like HD Tune, while mine was not reflected there. This is the very major thing that leaves my head scratching.

I'm running out of things to try and I have no idea why this is happening?
Really appreciate any suggestions and possible solutions, thank you!

I'm just going through probably a very similar problem with my 2TB WD Caviar Black SATA-II drive, circa 2009.

If you download WD's Data Lifeguard diagnostic software, see if it can run its "quick" scan. There is also an "extended" scan.

In my case the drive would not even complete its "quick" scan, and of course on the way to a complete "stall" at about 90% finished its performance was simply horrendous. Similar to your 1MB/sec, then it would speed up, then it would slow down, etc. But it wouldn't complete, and I finally had to cancel it (fearing damage to the head/platter if I let it sit there trying to error-recover indefinitely which is what I figured was going on).

It seems to demonstrate the problem when doing very large sequential operations where hardware cache would probably come into play... for example copying very large WTV/MPG video files from several hundred MB up to 30GB from the failing internal SATA drive to a second internal SATA drive.

I do not attribute this to fragmentation. I attribute this to drive failure.

After much patience (and probably good luck) I was eventually able to recover everything I had on this drive from backups, and from copying to an external USB 3.0 drive (which eventually succeeded, perhaps because it wasn't an internal SATA-to-SATA copy, or perhaps because it just eventually got past its read errors). Much relieved, I've now just done a second "batch of copies" yesterday which took about 45 minutes when it should have taken 10... but at least it completed.

I've already purchased a replacement drive (SATA-III Caviar Black) and will be making the hardware switch this weekend after the SATA-III 6.0GB/s data cable I bought gets here.

Very strange, as WRITE doesn't seem to be impacted as best I can tell. And small files seem immune to the problem. It seems localized to READ, and appears to show up reading very large files.

But in my opinion it's definitely a failing hard drive and the sooner it's replaced the happier I will be.

Thank you very much guys!

I have just defragged and rebooted after that, but it's still operating at that slow speed.
Fyi, The 1TB drive was 1% fragmented and 500GB drive was 3% fragmented.

Concerning the sfc and chkdsk, I have just started doing this, will report when done.

Regarding the WD quick scan, I have tried earlier today but it doesn't even want to start the process. I started the quick scan then it pops up the little window with the progress bar and the progress text on it. I have waited for about 10 mins nothing has changed. And btw, for me, the transfer speed is the same no matter how big or small the file is.
PS I will also be getting an external backup drive to backup my data on friday.

Thanks again!

The sfc scannow said it did not find any violations. And chkdsk /r has finished running.

Btw, should I try formatting the drive(after transferring the data away to another backup drive of course)? Thanks.

chkdsk on boot drive (500GB) completed in about an hour, I'm doing chkdsk on the 1TB now.
While only chkdsk-ed the boot drive, the performance is pretty much the same.

Will utilize the clean command few days later.

Thanks a lot! You guys are very helpful.

iExchange said:

Regarding the WD quick scan, I have tried earlier today but it doesn't even want to start the process. I started the quick scan then it pops up the little window with the progress bar and the progress text on it. I have waited for about 10 mins nothing has changed.

Again, sounds like my story. In my case it managed to "creep along" (projected time to complete estimated by the program at about 22 additional hours!!!) until finally reaching the 90% mark when it flat stalled.

I've simply decided the drive is failing, and works intermittently (if I'm lucky). Problem seems to show up with larger files, on READ only, but it's pointless to depend on the hardware when it's obviously undependable.

A replacement drive is the proper solution. In my case I'm going to upgrade from a 4-year old SATA-II to a brand new 64MB cache 7200rpm SATA-III since I have two spare unused onboard SATA-III connectors on the mobo. I would recommend you do something similar.

Focus right now on copying all the data on that failing drive (including all partitions on it) off to an external backup, as your failsafe.

I believe your failing drive is also your boot drive, so unless you are planning to reinstall Win7 from scratch and rebuild the whole drive (and all partitions) from the backups, you need to use backup software (e.g. Macrium Reflect) to hopefully be able to make a valid "system image" so that you can restore it to the replacement drive when you get it.

I don't think it is wise to spend time trying to coax your currently failing drive back to life. It's failing, and you don't want to lose anything because of it. Backup/image things while you still can. Then replace the drive with a new one. That's the right approach.