Laptop HDD extremely slow write speeds.

petefbi

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Dec 31, 2009
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Hi...
I'm banging my head with this one so appreciate any help here.

Situation:
A recent purchase of a Dell Inspiron 5755 refurbished laptop came with a 2TB Seagate ST2000LM003 HDD.
The default OS was pretty slow so I upgraded it to an SSD. No problem there.

I purchased a drive caddy converter to replace my optical bay and use the 2TB as a data drive.

This went all according to plan and everything seems to be okay.... until I write to the thing!

Transferring from the SSD to the 2TB HDD - Whether multiple small files or large files (multiple GB video or backups) the drive starts out well (70-100MB/sec) but then drops to single digits for MB/sec.
Task manager / performance monitor shows the drive's "Active Time" consistently at 100% but the transfer rate in the 1-2 MB/sec.

Transferring the other way (to the SSD from the HDD) is fine. No issues with Read Speeds.


Actions tried;

1) Replaced 2TB drive, in the caddy, with an Older 250GB WD hdd and repeated file transfers.
Drive reports up to 100% Active Time, but transfer speeds consistently 60-70MB/Sec throughout the transfers.

2) Placed the 2TB Seagate drive into a USB 3.0 external drive case.
Transfers to that device (from the SSD) would hit 100MB/Sec and hold steady for the full transfer!

3) Older WD 250GB drive also reported similar write speeds when placed in the external case.

4) Reinitialised the 2TB drive in both MBR and GPT formats to see if any compatibility issue. I need the drive as one, big data drive so no concerns if either format.
After each init and format, ran the above tests again with the same results.


I first assumed that the drive was duff, but I can't ignore the external USB case results that give me 100+MB/sec transfer speeds.

I would really like to have this drive internal to the laptop without having to have an extra USB device.

Thanks in advance for any assistance.

 
I'm not looking for SSD performance.
I'm looking for a reason why it will write to the HDD at 100+MB/sec while it is in a 3.0 USB case, but at only 1-2MB/sec connected to an internal caddy in the laptop.

As I stated in my tests I used an *even older* mechanical HDD in the same configurations and it was working consistently 60-70MB/sec in either the internal caddy or the USB 3.0 case (which is all I want from the newer 2TB drive).
 
Please check to see if there are any BIOS updates available for the laptop. There might be something in an update that improves performance with foreign SATA devices.

Many times, with laptops, the SATA controllers are specifically built to communicate with the drives put in the laptop by the manufacturer. This means that they can save a few pennies on the SATA controllers. Save 3 cents on one laptop, produce 1,000 laptops a day, save $30.
 
The 2TB HDD is the original drive that came with the Dell (verified on their website according to the Service Tag of the machine).

If the HDD was just bad I would assume that there would be similar bad performance in whatever way it was connected. It's just this drive in the internal caddy. Other HDD in that same caddy work.

Any other tests I can perform other than mentioned above?
 
No difference in speeds when configuring it with a 250GB partition.

I've since liberated another 500GB HDD from another laptop and ran the same tests. Everything works fine with it in the internal caddy as the laptop's second drive. Speeds of 60+MB/second write speeds (which I'm more than happy with for a secondary drive).

The original 2TB (that has the issues) is now living in the external USB 3.0 case and will run at speeds between 60-100MB/second when being written to.

I can't even think of what causes this other than a unique situation between this particular model of Seagate (ST2000LM003) running on the Laptop's SATA interface (be it in the primary connection or the secondary).

Any last thoughts before we close this?
 
The up to date firmware is already on the drive.
I'm going to leave it in the external case as it works fine there.
The smaller 500gb HDD is also working great in the internal caddy behind the SSD.
I'll chalk it up to being one of those strange compatibility errors that can't be explained.