[SOLVED] Very slow HDD write speeds

r4ptor

Reputable
Nov 30, 2015
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4,520
Edit: Solved by swapping SATA cables

I own 3 WD Black harddrives: WDC WD4003FZEX-00Z4SA0

One of these tops the read speed at 180MB/s while the write speed tops at 15MB/s and I can't figure out why. The other drives are much faster.

I've tried googling but couldn't come up with much.

I hope anyone in here can help me out.

Ps. I recently checked the entire drive for errors using HD Sentinel.

Off-line uncorrectable sector count jumped to 1 a week or two after purchase, about a year ago. Then 2 approx 8 months after purchase. Now back to 1 after I tested the entire drive using HD Sentinel.

 
Thank you for your replies - I appreciate it.

I stumbled upon a post somewhere, about someone having similar problem. He found the solution by swapping SATA cables and since it's a very quick thing try out, I figured, why not try it myself.

I swapped cables with another drive that I had just beforehand tested the read and write speeds of.

The roles changed. The other drive now had write speeds topping at 15MB/s while the one I originally wrote about, was topping at 130MB/s during a copy operation (same size of files as before).

A bad cable, I suppose? That particular cable, with the slow write speeds, have been bent 90+ degrees to make it fit at the button-most HDD slot, and I guess it's quiet a bit old now. Older than any of the hard drives I have.

I'll see if I can find a different cable - it's interesting though, with the limited knowledge I have about such matters, that the read speed is still blazingly fast.
 
I found a never used before cable but sadly, it did not help.

I then had a look in BIOS, to see if there was something there I could tweak - didn't appear so, but while being in there, I had a look at the Hardware Monitor. My 3.3v output is at 2.9v and marked in red. I can't find proper answers for this, but perhaps this is the reason?

I'll have to get a new PSU no matter what, that's for sure. Btw, the low writing speeds always/only occur on the last drive (highest drive number in BIOS and Windows). I have 5 HDD's + DVD, currently being powered by a 850W Corsair PSU. That PSU might be some 6-7 years old now.
 
Hey there, r4ptor!

I'm sorry to hear about your performance difficulties with the WD Black! 🙁 I'd recommend you to test the HDD with WD's Data LifeGuard Diagnostics for Windows either way. Running the QUICK and EXTENDED tests will help us determine the SMART status and health of the drive. You can even benchmark the results you got from the other diagnostic tool.

If you suspect power supply issues, then you should check the power management requirements for the WD4003FZEX. Another way to troubleshoot whether or not this is the source of your issues, you can simply plug the WD Black to a different computer and test its transfer speeds there. If everything seems to be performing flawlessly there, then the sooner you upgrade the current PSU, the better.

Keep us posted. Hope I was helpful! :)
SuperSoph_WD

 
SuperSoph_WD, thank you for your reply.

I downloaded Data Lifeguard but was not able t run it. It stops working after I acknowledge License Agreement. I had already done a so called Reinitialize test from HD Sentinal, and found no further problems and it "fixed" a bad sector. According to SMART, which I monitor daily, the first bad sector appeared only few weeks after purchase a year ago. The second one appeared 8 months later. The Off-Line Uncorrectable Sector Count is currently 1.

I placed an order for a new PSU and it should arrive shortly, but I'll see what else I can do to test the HDD, like running it from a different computer.
 
I'm not familiar with Hirens, but just googled it - I also just received a message from the postal service telling me, that my PSU will arrive tomorrow. I'll actually install the PSU first, as thoroughly testing a 4TB drive with software will probably take ages.
 
The PSU didn't help - but I have proper voltage output now and a very silent PSU, so it wasn't all in vain - the old one was very dusty and noisy.

I swapped SATA ports with a third drive - and that did the trick. When I swapped the first time, it was a WD of same model and the problem was inherited. This time I swapped with a 4TB Seagate drive.

Read speeds on all harddrives are 150+ MB's and write speeds 125+ MB/s - I'm not sure what and why, and I think I'll just leave it here (but keep an eye on performance for the time being).