How to make an SSD drive work on SATA 3?

Question

Samsung

Got myself an SSD. Specifically Samsung 840 EVO.
Turned on AHCI, reinstalled on the new Windows 8.1. The disk works, but in the standard Samsung Magican utility I get this message:
"The SSD drive will not be able to work at maximum performance because your system does not support the SATA 6 Gb / s (SATA 3) port"

Motherboard Gigabyte GA-990XA-UD3 rev 1.1 has SATA 3 ports...
Performance tests show lower than expected (Sequential read 238 Mb / s)
Bios settings are as follows: I installed the

drivers from the disk, but I don’t know how to see if everything is fine with them.
So how do you get this SSD to work over SATA3?
This is what the drives look like in Device Manager:

Answer 1

Usually there are sata2 and sata3 ports on the mother, it is logical to plug from sata2 port to sata3.

Answer 2

As an option: Try to install the chipset driver from the manufacturer's website.