The 390 does not have PCI-E 3.0 slots. There is an inherent incompatibility with PCI-E 3.0 and older versions of cards. This is because the power profile AND the clock speed of the bus does not DOWNGRADE to 1.0 or 2.0 speed. If you need 802.11 Dual band use a USB Wifi Adapter like the
EIDEMAX AC600 usb adapter.
I have the same problem. In my case I am using a totally different network card, but the results are identical. My card is an Intel® Gigabit ET2 Quad Port Server Adapter. PCIe v2.0.
Speed & Slot Width: 2.5 GT/s, x4 Lane
Controller: Intel 82576
Just to verify, you are inserting the card in the #16 PCIe x4 slot 2? The slot closest to the #15 internal buzzer?