madsriisager

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Sep 23, 2014
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Hello

My problem is that I see low internal tranfer speeds between harddrives. The files vary in size, but they can be from 40 to 80 GB. The file transfers will start at maybe 170 MB/s, and then they slow down to 3-4 MB/s, sometimes 700 kb/s. And it seems to be one way sometimes. Like if I tranfer files from one disk to another it will have an average of 90 MB/s, but the other way around they will be at 3-4 MB/s.

I know my system is old, but i don't see if that should be the cause of the bottle neck? My specs are:
CPU: i5-3570K 3.4 Ghz
RAM: 24 GB
GPU: GTX 760
Motherboard: MSI Z77 mpower
Harddrives: ST8000AS0002
OS harddrive: Samsung SSD

What might be the cause of this bottleneck?
 
Solution
one of your HDD might be heavily fragmented or near end if its usable life. Try defragmenting it. I would suggest formatting if possible. defragmenting puts excessive wear on drive and does't improves things that much.

Also it's an archive drive intended for mostly reading files. other people reported poor write speeds because of overlapping tracks.

haseeb98ahm

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Jan 30, 2018
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is it a single 40 to 80gb file?
are you transferring between your HDD and SSD? if yes then of course copying to SSD will be much faster than copying to HDD because SSD write speed is much faster.

Is copying from SSD to HDD causing speed to drop to 3-4 MB/s? well thats HDD write speeds. It's initially faster because of HDD's cache. data is written to HDD's cashes and that's what gives you 170 MB/s write speed but when cache gets full you're writing directly to the disk platter.
 

madsriisager

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is it a single 40 to 80gb file?
are you transferring between your HDD and SSD? if yes then of course copying to SSD will be much faster than copying to HDD because SSD write speed is much faster.

Is copying from SSD to HDD causing speed to drop to 3-4 MB/s? well thats HDD write speeds. It's initially faster because of HDD's cache. data is written to HDD's cashes and that's what gives you 170 MB/s write speed but when cache gets full you're writing directly to the disk platter.

Yes it is a single 40 to 80 GB file. The transfer is between two HDD, so the SSD is not involved here.

On its product page the internal write speed it set to 150 MB/s, and as mentioned I have sometimes sustained average transfer speeds of 90 MB/s for 80 GB files one way, and then the other way it will drop to 3-4 MB/s even though the HDD are of the same model.
 
Last edited:

haseeb98ahm

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Jan 30, 2018
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10,615
one of your HDD might be heavily fragmented or near end if its usable life. Try defragmenting it. I would suggest formatting if possible. defragmenting puts excessive wear on drive and does't improves things that much.

Also it's an archive drive intended for mostly reading files. other people reported poor write speeds because of overlapping tracks.
 
Solution

madsriisager

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Sep 23, 2014
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Thank you, I'll will give it a try! But I don't have that much left over space, but I will see if I can't get the files moved, and the problematic drive formatted.

I will mark your answer as best solution, as soon as I have made sure, this was the cause of the low write speed.