Yes, I figured that the 6G ports dont like the drive at all, hence undetected, but the behavior when connected to the 3G ports is far more puzzling. Its almost as if the drive is constantly being interrupted. Normally I would blame the drive but as I said it works perfectly on several other platforms (the closest of which is the Q75 I tried it on).
BIOS on the DH77KC is absolute latest as of this writing (0110).