Sure, check the cables, that can be a point of failure there (I thought we did check em previously though?). As for marking this as solved, it's evident what we're dealing with here, in that it's either disk or cables to disk (motherboard issue is very, very unlikely). I say get an RMA on that drive if possible. You can mark this solved once you are confident on the diagnosis.
Yes, I have tried with different SATA cables as well as changing the SATA port to a point where I've ruled that out as the cause. The only thing now that I haven't tried is another PSU, but since things are running smooth with the other drive, I've assumed that's not the issue either.
Now the next tricky part is convincing SanDisk to give me an RMA. I don't feel like I'm making that much of a progress though, since the support guy is asking questions I've already given him the answer to :/
Sometimes it's a gamble. If one support tech is causing you grief, just tell them you'll call back and then call again and hopefully you'll get another tech that's easier to work with. I've deal with techs for hours on situations, and then when calling back I'd get another one who'd let me through with the RMA almost immediately.
I know what you mean, been there in other issues. Oh, the anecdotes. Such a clear difference between them who are obviously reading from a step-by-step guide, and those who actually know what they're talking about.