I have a Sonnet SSD Pro Plus that was originally intended for use in my Mac Pro, but due to it preventing booting from the Bootcamp drive, even when that drive is not connected to the card, I have decided to repurpose it and put it in my Z77X-U5DH based system. However, even though the card and SSD drives (both Samsung EVO 850 1TB) are detected in older systems with PCIe slots, on the Z77X, it is as if the card isn't there. I have tried shifting the card to other slots, with no avail. The slots work fine with other PCIe cards, such as graphics cards.

I'm starting to wonder if a) there is a conflict with the onboard Marvell chipset as I believe the card is also Marvell-based (91xx chipset) or b) if the BIOS lacks a module that would be required to allow it to see PCIe based storage. As far as I know, the card is AHCI-based, not NVMe. That it works on older PCIe mainboards certainly suggests that this is the case. And, yes, I need this card. I have other drives attached to the board's SATA ports.

Could anyone point me to where I might look to begin to solve this problem?