Why does my additional internal HD lag when copying files?

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Level 1

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Why does my additional internal HD lag when copying files?

Purchased the OWC data doubler and replaced my super drive with a HGST 1TB Travelstar 7K1000. My start-up disk is an SSD and gives me no problems whatsoever. The new HD is recognized and can read and write data. However copying files and accessing data consistently lags. AJA System Test revealed the disk writing and reading at ~100+ MB/s. However when copying large files it stalls out for long intervals of time but will eventually finish the copy. This performance issue makes the new HD virtually unusable. Is it a lemon? Or is there something else going on?

MacBook Pro, OS X Mountain Lion (10.8.5), 2.8 GHz Intel Core i7

Posted on Jan 20, 2014 4:43 PM

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Answer 1

Jan 20, 2014 4:48 PM in response to dutchdubs

The OWC data doubler is very junky in mfg. Id test the Hitachi (best made) HD externally FIRST and verify thats not the case

if it isnt, its the junky made OWC data doubler.

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Answer 2

Sonicray

Level 5

4,555 points

Jan 20, 2014 5:20 PM in response to dutchdubs

Also, depending on which MBP you have your main SATA link is 6GB/s the SuperDrive SATA link is 3GB/s. So, it is slower than your main drive...

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Answer 3

dutchdubs Author

Level 1

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Jan 20, 2014 5:35 PM in response to Sonicray

Late 2011 MBP. So I think this may apply. But even if 'slower' read/write times are to be expected could the SATA link difference really be enough to cause it to hang or stall like this ?

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Answer 4

Sonicray

Level 5

4,555 points

Jan 20, 2014 5:38 PM in response to dutchdubs

Knowing that you are using the OWC data doubler , it could be that there is a loose connection in there somewhere?

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Answer 5

BobRz

Level 5

6,138 points

Jan 20, 2014 5:58 PM in response to dutchdubs

It could be the SATA cable that goes to the Data Doubler. I use one myself and it runs just fine.

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