SATA Raid 0+1 problem

[KBeee]

I have a Raid 0+1 setup, which since I built this computer has given me problems.
The setup is four Western Digital RE2 500GB HDD's (WD5000YS) connected to an ECS PN2 SLI2+ (nVidia 680i) motherboard.
The problem is that the array keeps losing 1 HDD, necessitating a rebuild, which the raid controller starts automatically.
As soon as the array is rebuilt to 100%, it loses the drive again, and rebuilds again in a continuous loop.
The WD RE2 HDD's have a known problem in SATA raid arrays, which is supposedly overcome by flashing the hard disk firmware from V7.2 to V9.2, which I've done.
Also the 680i MB has known SATA raid problems, supposedly overcome by updating the MB bios (from the original P21 bios to the P28 bios), which I've also done.
The SATA cables supplied with the motherboard didn't seem to have a very positive connection and felt very loose, so I changed them for Akasa SATA cables that clip more securely to the motherboard and HDD's.
Still the problem persists.
This is on a Win XP Pro SP2 OS
Can anyone give me any pointers on what to try next to overcome this problem?

[streetster]

is it the same drive that keeps failing... have you ran a hardware diagnostic on the drive to rule out it being faulty?

[KBeee]

I've tried running WD's drive check utility, but for some reason it doesn't work. I mailed WD's support about this, but got no reply.
I think it's the same drive failing - SATA Drive 1.0 (i.e. never says 1.1, 2.0 or 2.1).
Having a little think about it, I reckon I should try putting the 1.0 drive onto another SATA channel (there are 6 on the 680i MB), and see if it still fails. That should rule out the MB being faulty

[GoNz0]

test it out of the raid array