I've made a RAID-0 through the Gigabyte GA-Z77-D3H bios with two 500 GB HDD. Occasionally, one of them would be marked as failed during the start up and Intel's utility would indicate 'anomalous state' and give the chance to correct it.
I've unmade the RAID to check the disk. It failed seatools long test once (and passed it another time) and the smart data seems to be ok.
Do you think the matter is related to the hard drive, the raid and, is that hard drive useful for something else than a being a paperweight?
Here's a screenshot of the smart data, obtained through crystaldisk info