I bought me new pc components including the motherboard GA-970A-UD3 (rev 3.0) from Gigabyte. First I installed Windows which worked without any problem. Then I tried to boot my existing Arch Linux partition.
The Realtek RTL8111/8168 LAN controller was correctly identified by the kernel but when I tried to establish a lan connection the receiver recieved no packages at all. Another problem was USB 2.0. Only USB 3.0 ports worked.
After half a morning of searching and trying to solve the problem, I found the solution on Arch Linux Forum:
teekay wrote: > “You need to enable IOMMU in the BIOS of the Gigabyte board.”
That’s it. After I did that the network and the USB 2.0 ports work fine.