Question Internal HDD sequential speeds reduced to half even though it is working in SATA III mode.

Agera One

Distinguished
Sorry for the long post, I want to give as much details as possible!

I have 2 HDDs in my PC:

Disk 1 - WD10JPVX - 1TB 2.5" 5400rpm internal HDD (been using this in my laptop for 5+ years, now using in my new PC for 5+ months)
Disk 2 - ED40EZAZ - 4TB 3.5" 5400rpm internal HDD (bought specifically for this new PC)

Yesterday, my cousin came with his laptop and I wanted to copy large files from him and he wanted something from my computer. What I did is turned off my computer, drained the power and removed the SATA data/power cables from the Disk 1 (1TB HDD), removed the HDD cage from my computer and connected to his laptop with the help of this USB-to-SATA cable, copied all the stuff to and from.

When I assembled back everything into my PC, I turned on everything was back there where it used to be but the files I copied from him are not showing (but the space is conquered) in the 1TB HDD. I googled possible causes, one Tom's hardware thread showed "turn off fast boot in BIOS and turn off fast start up in Windows and try". I did exactly this and got my files to display in file explorer. Copied them to the 4TB HDD and then re-enabled Fast boot and Fast start up.

Now coming to the title, something urged me to benchmark this 1TB HDD and I found that it's sequential speeds are reduced into half in CrystalDiskMark64??? Benchmark done on 4th April, benchmark done today.
No hardware changes, SATA data/power cable changes, etc ever in my PC.

What I tried to solve this:
  1. Copied a large game recording file (50GB+) and noticed the 1TB HDD speed in task manager, still it is half like in the today's benchmark image.
  2. Used AS-SSD benchmark, same reduced results in the 1TB HDD.
  3. Swapped the SATA cables between the 1TB and 4TB HDD. The 4TB HDD speeds are not changed, they are the same when new and today, but the 1TB HDD still showed reduced speeds (tested with 2 benchmark apps and large file copying as stated above)
  4. Swapped the SATA ports between the 1TB and 4TB HDD. The 4TB HDD speeds are not changed, they are the same when new and today, but the 1TB HDD still showed reduced speeds (tested with 2 benchmark apps and large file copying as stated above)
(In steps 3 and 4, I ensured the SATA data/power cables are fully plugged in both sides, so I'm 100% sure cables are not loose)

What could be the problem and how do I get back the true speeds?

Latest Crystal Disk info snapshots - 1TB HDD - 4TB HDD which shows they're still operating in SATA III mode.
 
Last edited:
Sorry for the long post, I want to give as much details as possible!

I have 2 HDDs in my PC:

Disk 1 - WD10JPVX - 1TB 2.5" 5400rpm internal HDD (been using this in my laptop for 5+ years, now using in my new PC for 5+ months)
Disk 2 - ED40EZAZ - 4TB 3.5" 5400rpm internal HDD (bought specifically for this new PC)

Yesterday, my cousin came with his laptop and I wanted to copy large files from him and he wanted something from my computer. What I did is turned off my computer, drained the power and removed the SATA data/power cables from the Disk 1 (1TB HDD), removed the HDD cage from my computer and connected to his laptop with the help of this USB-to-SATA cable, copied all the stuff to and from.

When I assembled back everything into my PC, I turned on everything was back there where it used to be but the files I copied from him are not showing (but the space is conquered) in the 1TB HDD. I googled possible causes, one Tom's hardware thread showed "turn off fast boot in BIOS and turn off fast start up in Windows and try". I did exactly this and got my files to display in file explorer. Copied them to the 4TB HDD and then re-enabled Fast boot and Fast start up.

Now coming to the title, something urged me to benchmark this 1TB HDD and I found that it's sequential speeds are reduced into half in CrystalDiskMark64??? Benchmark done on 4th April, benchmark done today.
No hardware changes, SATA data/power cable changes, etc ever in my PC.

What I tried to solve this:
  1. Copied a large game recording file (50GB+) and noticed the 1TB HDD speed in task manager, still it is half like in the today's benchmark image.
  2. Used AS-SSD benchmark, same reduced results in the 1TB HDD.
  3. Swapped the SATA cables between the 1TB and 4TB HDD. The 4TB HDD speeds are not changed, they are the same when new and today, but the 1TB HDD still showed reduced speeds (tested with 2 benchmark apps and large file copying as stated above)
  4. Swapped the SATA ports between the 1TB and 4TB HDD. The 4TB HDD speeds are not changed, they are the same when new and today, but the 1TB HDD still showed reduced speeds (tested with 2 benchmark apps and large file copying as stated above)
(In steps 3 and 4, I ensured the SATA data/power cables are fully plugged in both sides, so I'm 100% sure cables are not loose)

What could be the problem and how do I get back the true speeds?

Latest Crystal Disk info snapshots - 1TB HDD - 4TB HDD which shows they're still operating in SATA III mode.
Defrag the 1TB....test.
 
Thanks. You can see that reading/writing at the outermost cylinders is about twice as fast as the innermost cylinders.

That said, I can understand why CrystalDiskMark would produce slower write results when the drive becomes full, but I can't understand why this should affect the read results. Also, I wonder how HD Tune managed to perform a non-destructive (?) write test on a filled area of the drive (I only asked for a read graph).

Edit:

Your 4TB drive appears to be an SMR model, so you can expect a drop in performance during sustained writes.
 
Last edited:

Agera One

Distinguished
I wonder how HD Tune managed to perform a non-destructive (?) write test on a filled area of the drive (I only asked for a read graph).
I emptied my 1TB drive and performed the rite test.

Your 4TB drive appears to be an SMR model, so you can expect a drop in performance during sustained writes.
Yes, I know. I looked for WD40EZRZ, the CMR version at 5+ stores, no stock anywhere here in my country. So, I went for the SMR variant.
 

ASK THE COMMUNITY