870A-UD3 and WD Green Drives Issue

[albundyhere]

Hi, I got a 870A-UD3 and noticed that all my 3 WD 1TB Green hard drives (WD10EACS-00ZJB0) perform very poorly when connected to the SATA 3 connectors.  I am getting no more than 15Mb/sec write speeds under AHCI.  But, when connecting 2 of the same green drives to the SATA 2 white ports, I get 70-80Mb/sec under IDE mode.  These drives are originally SATA 2 drives, so I am baffled as to why I am getting such a large performance hit.  Is there any suggestion as to what I can do at this point? I also have a Hitachi 2TB 7200rpm drive and a Sandisk Extreme Pro attached to the SATA 3 ports with no performance issues, if that makes any difference.

[AgentFXA]

These drives are supposed to be native sata3 disks but since your mobo is 4+ years old there may be a compatibility issue. If it works fine on sata2 ports just use it there.

[dmdilks]

I don't if this will help: http://wdc.custhelp.com/app/answers/detail/a_id/1431/p/227%2C294/session/L3RpbWUvMTQxOTE2NjkwNS9zaWQvakpoTDVzYW0%3D

[albundyhere]

These drives are supposed to be native sata3 disks but since your mobo is 4+ years old there may be a compatibility issue. If it works fine on sata2 ports just use it there.

My 1TB WD10EACS green drives are sata2 native.  my other drives are all sata3 native.  still, there should be no performance hit.  that leaves me with 1 green drive that is slow as heck, so i will have to live with it until i can get an esata 4 bay enclosure for all of them.  the one thing that i have not tried is to set the sata3 ports #4 and #5 to ide mode since those two ports are on a separate controller.