Inspiron 5547 with R7 M265 can only run on integrated GPU

I'm using an Inspiron 5547 with Windows 8.1, recently I've just noticed that it has low fps for all games even though the settings are set below average. Thus, I've updated the GPU driver with the one provided at Dell Support and nothing changed at all. Here are the few points that led me to believe that it's running on integrated GPU all the time,

1. On Speccy, I can't get a read on the correct temperature of the GPU, it's shown as a ridiculous value of 511 celcius.
2. On CPUID, there's no detail at all on the dedicated GPU.
3. In the Intel HD Graphic Control Panel, I can only choose profiles for Built-in Display.
4. On AMD Catalyst Control Center, I can't get any information of my GPU at Information > Hardware or have any settings of the graphic performance available to be changed.

Any help is appreciated, thanks.