I connected a hard drive to the gray SATA port that the Blu-Ray drive was connected to, and it works just fine. No hard hangs (or at least I can't reproduce one after six or seven attempts).
Yes, the Marvell controller. So my question is: are there any drivers for this discrete chipset for Windows 8.1 Pro 64-bit that I'm missing? My last Intel motherboard also had a mix of Intel and Marvell, and the Intel always worked great and the Marvell...not so great.
BIOS: KLZ8711D.86A.0450.2014.0217.1636 (2/17/2014)
The current Blu-Ray drive is Pioneer BDR-209DBK (version 1.10 - current).