I have an RX 560 and an A8-7560K R7.
In the menu, there is no "switchable graphics tab" and I can't seem to find the additional settings button either.
Temporarily I am required to use the A8's graphics alongside with the RX 560's but any time I run a game, it defaults to the A8's GPU, though I need it to use the RX 560.
Radeon Settings Version 2018.0911.1425.25970
Driver Packaging Version 18.30.17.01-180911a-333148E-RadeonSoftwareAdrenalin
2D Driver Version 184.108.40.2064
Direct3D® Version 9.14.10.01359
AMD Mantle Version 9.1.10.0278
Vulkan™ Driver Version 2.0.49
Vulkan™ API Version 1.1.77