I just installed a WD 250 SATAII hdd in my computer which already had 2 pata drives in it. My mobo is only compatible with sata I so I jumpered the drive as shown on WDs' site to keep it at the 1.5gig transfer rate of my mobo. My bios saw the drive for what it was(scsi device, which as I understand, is fine), it showed up in disk management and the device manager as a 250gig drive, my drive speed software was able to test its' performance. I thought all was good until I tried to transfer some files, I would get a popup that said something like "I/O device error". I ran WD diagnostics and it said there was a cable problem, it also saw the drive as an eide drive. I tried a different sata cable and both types of power connectors, but nothing worked. I went to the mobo man. website to look for a driver, all I found was a SATA RAID controller. I dl'ed and installed it and now the drive works fine, WD diagnostics shows that everything is good and sees it as a SATA drive and I can transfer files to it. So what does this mean? Do I need a raid setup with 3 drives or is it the mix of sata and pata, or did the raid controller happen to have a sata driver in it that I needed? I am not familiar with raid or how to set it up, I thought it was for using multiple drives as one mass storage device. I did some studying on raid and I don't see how it relates to my situation. Could someone enlighten me?