Slow Esata and USB 3 speeds

Ok. I am completely stuck here. I have two external raid arrays. Both are arranged in a Raid 5 and have 4 Seagate Barracuda 3TB drives in each. I have zero'd out the drives and checked them for errors using Seatools, so I know all the drives seem to be functioning well. When I run a benchmark on each of the Raid 5 arrays I see an average speed of 180MB/s over esata. Also, when I transfer a large file from the raid 5 to the SSD inside my laptop I see a stabilized speed of 140MB/s. However, when I transfer from 1 Raid 5 to the other Raid 5 it stabilizes at 30MB/s.

I have tried the transfer with both drives connected to USB 3, both connected to esata, and one connected to USB 3 with the other on esata. It always stabilizes at 30MB/s. Have updated all my drivers and still nothing. Please help me understand what is going on?? I have 5TB of data to transfer and this is going to take forever!
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More about slow esata speeds
  1. what is the model of your raid5 box?
  3. Best answer
    Hmm this box should do about 200MB/s.

    I hope your Seagate HDD is not a new series STxxxxDM001.

    The last time we used 2TB STXXXDM001 in RM5_R5 a five bay 1U rack mount hardware raid. The results is very funky in write
    It is very fast at first, but then it slows down to a craw.

    I tried all to force the HDD ran as 1.5/3.0... It does not help.
    But the I switch the HDD to Hitachi we got 245MB/sec

    Go Figure!
    I think it's the HDD, try other brand of HDD and see your result is same as mine
  4. Well that resolved it. I was using the Seagate St3000DM001 series drives and they are not supported in Raid 5. I thought for sure they were. So, I swapped to Raid 10 and now have over 300MB/s speeds. Thanks Firewire2!
  5. Best answer selected by mediabrewer.
  6. Thank you!

    That confirm my expected cause is not crazy!
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