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I ran the HDTune drive monitor while I was transfering about 80 GB of various sized files, most of which was running about 40 MB/s, but you can see where it spiked down to under 1 MB/s.

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I ran a few more tests with HDTune. It seems one of these drives is having some issues:

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Is this perhaps just a faulty drive?

I will try a few more transfer tests between both HDD and a third HDD to see if I can get some consistent higher speeds.

When deleting files it can drop from 700 items to 200.

New motherboard - GA-990FXA-UD3

New HDDs - Samsung 2 TB HD204UI

New SATA cables - came with the motherboard

File transfer speed from one to the other can go anything from 150 MB/s to under 100 KB/s.

A typical file transfer could be an 8 GB ISO file, it will start off at about 150 MB/s flying along, but as it goes it will slow right down, usually to about 15-30 MB/s and occasionally right down to below 100 KB/s.

I have tried disabling antivirus (Avast!), no change.

I have tried an alternative transfer method/program (TerraCopy). It gives a more stable transfer speed, but it's still quite low, usually a solid 15 MB/s.

And I have checked both drives with HDTune, which reports no obvious problems for either drive.

What can I do to diagnose this further or better yet, fix this?

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If you ever have doubts whether you have a faulty drive, start with the drive manufacturer's diagnostic. In this case SeaTools. – Jason Jul 29 '14 at 15:03
Just because the SATA cables are new does not mean they work properly. – Andrew Morton Jul 21 '15 at 17:25

Anything at all that is accessing those drives will slow the transfer, as will CPU usage elsewhere.

You could run ProcMon and turn off all monitoring except the drive to see what is accessing it. Defraggers with monitors may be the worst offenders.

Heavy fragmentation (unlikely) and file system errors (chkdsk) will both slow transfers, too.

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I don't think its anything in the background, it can run at 150mp/s i have done a few transfers at that speed on the same drives, check my updates, im pretty sure the drive is faulty in some way. – Brae Jul 18 '11 at 8:56

You need a new methodology.

The way to diagnose it is to copy files to a separate drive. Trying to bench mark a drive by copying files onto itself is like measuring one's dexterity by trying to see how fast you can put sunscreen on your back!

The drive basically has to copy files back and forth from two discrete areas of unknown distance.

And it's even worse with teracopy's dynamic buffering. Teracopy's dynamic buffering was great for XP, but Vista n 7 use a new algorithm for copying files, so sometimes they conflict with each other. This is especially noticable in read/writes across a network.


I wouldn't trust the dialog box either. Use performance monitor and add the Disk read/write counters. Try to find some rather large files. Ripped DVDs are perfect for this. You don't want a bunch of small files because that will screw with your benchmark. And don't use Teracopy. It's dynamic buffers will screw with your numbers. By far the best feature about teracopy is it's pause and resume, not speed.

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The asker is already using two separate drives. – Ignacio Vazquez-Abrams Jul 18 '11 at 7:12
Didn't see the (s). I'll edit my answer. – surfasb Jul 18 '11 at 7:14

Your HDTune benchmark results you posted are not bad--they are what you should expect for that drive. Transfer rates will range dramatically depending on block size and other factors.

As a reference, here is professional review for your drive. They report 4 KB block random transfers to be less than 1 MB/s, and 2 MB block sequential transfers to be over 100 MB/s.

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up vote 0 down vote accepted

Probably a faulty drive, i forget what happened. Self answering to close this 4 year old thread.

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