We have a MSI 970A-G43 motherboard which generally works fine. We have 4 hard disks attached and a BD drive. We have not had problems with the machine.
We own a front panel card reader box with USB 3.0 ports. It also has fan control which was intended to augment the motherboard.
When we connected the card reader to the machine, the second hard disk D: was disabled and the card reader took over the D: drive letter. The hard disk was not reassigned to another drive letter, instead it was crashed and needed to be power cycled and connected to a different machine to be recovered.
It seems that the UEFI BIOS was not able to enumerate the card reader and hard disk properly. Windows also was very slow to boot as it attempted to communicate with the UEFI to figure out the hardware. This is a rare BIOS fault that we only recently were able to identify. Clearly the hardware enumerator has some issues to be fixed.
We have another external USB card reader to handle memory cards so we are still able to get photos from camera etc.