[SOLVED] New external HDD has sometimes slow transfer speed

szerwony

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Hi. Recently I bought ADATA HD680 external HDD. I noticed, that sometimes it has slow transfer speeds - up to 15 MB/s. When this problem occurs, I need to disconnect drive from PC and then connect again. After reconnecting, speeds are great - up to 110-120 MB/s. As for now it happened only 3 or 4 times, but I don't know what causes this problem and if I need to return drive for repair.
 
Does this only happens when connected to one particular computer?

Does it happens when transfering large files (e.g. several big iso image files) - or when you're transferring many smaller files?

Does it behaves the same regardless of wich way the files are transfered ?

What file system, and is it close to be filled up ?
 

szerwony

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As for now it happened with two different PCs.

It happens with both large and small files.

For now I only noticed it when copying files to external drive. One time I also ran CrystalDiskMark, when slow transfer happened, and only write speed was slow. Read was ok. Problem disappeared after reconnecting.

I think it's FAT32, but I will need to check it later because I am not sure. It's almost empty.
 
It may come down to the disk itself. Can't remember excactly where I saw a comment on this forum and neither can I remember the disk type an manufacturer in that case.
But it came down to the way of writing data to the platters, so that it use cache much more extensively than other disks, and thus the write speed is reduced.

Hopefully some forum users can recall better than me :unsure:
 

szerwony

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Copy files of what type and size?
A batch of small files WILL copy slower than a single file of the same cumulative size.
For example 5 video files, about 10GB in total. One time they copied with speed 15MB/s, but after reconnecting drive, same files copied with 110MB/s.

But it came down to the way of writing data to the platters, so that it use cache much more extensively than other disks, and thus the write speed is reduced.
And simple reconnecting disk solved this problem?
 

szerwony

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Yes, here are SMART values from HD Tune:
xwCnHPz.png
 

szerwony

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I mean that it doesn't matter to which USB port I connect disk. Problem can happen on every USB port. On second PC I tested it with one port only and problem happened only once.