RAID 10 problem

Motherboard - ASUS P8P67 EVO R3.0 Intel P67 LGA1155
4 HDDs - WD Caviar RE4 2 TB WD2003FYYS 64MB (RAID edition).

I have a RAID 10 setup out of 4 HHDs on build-in on-board Intel RAID driver. 

It was working brilliant for a month. Then suddenly, during startup, some strange, unnatural continuous sound (resembling a tractor working) came from one of the drives and the computer stopped booting up for a while. After boot-up this sound and lagging occurred very frequently. Then Intel RAID driver indicated a disk malfunction and disconnected the drive. Indeed, the disk indicated some SMART errors (write errors in particular). 

I disconnected the drive cable - everything came into perfect life again. I thought it was a HDD problem - but it wasn’t. 

The same problem started with another drive of the RAID array that was connected to different port.

  1. What may be happening here?

  2. I guess it’s a MB problem - is is rather hardware problem or software?

  3. What RAID controller should I buy to resolve the problem? - Is that a solution?

Just to furher clarify:

The Smart indicates problems in the following parameters:

Ultra ATA CRC Error Count - 2
Write Error Rate - 6

BUT: I replaced the cable - problem still persists. So it’s not cable issue.