Well, seems to me that you have integrated graphics(intel) and dedicated graphics AMD HD8790M (perhaps with 2GB GDRR5), with AMD Enduro technology.
→ Enduro technology what allows the HD 8790M to switch between integrated and discrete graphics so as to increase battery life of notebook.
As your card is GCN(Graphics Core Next) generation,you can use,amdgpu or amdgpu-pro driver..
Amdgpu-pro driver you can use,but is only supported on Ubuntu 16.04 LTS,and that is what you use..
I recommend for you to use amdgpu-pro ,and to install it you need to follow link from amd page.
Amdgpu (without pro) is open source driver you can use it too,but then you do not need to follow that procedure.(procedure is different,esp.for best top results,and that will be your only option if you upgrade from 16.04 up ,seems till next LTS)
To use amdgpu-pro, what not came with ubuntu LTS but is build and tested from AMD company to use it with Ubuntu 16.04 LTS ,you need:
Note1! You do not need to install that SDK..if you dont have plan to build applications...
Note2!→Really i enter for you, and check on AMD page,notebook linux drivers,ubuntu and Radeon HD seria,Radeon 8700 seria,and get redirected to amd-gpu -pro page...(if someone else reading this is GCN card!regardless HD prefix )so if you wanna use amdgpu-pro ,first download driver package from link for ubuntu from amd page→
http://support.amd.com/en-us/kb-articles/Pages/AMDGPU-PRO-Driver-for-Linux-Release-Notes.aspx (today is this version on page→AMDGPU-Pro Driver Version 17.10 for Ubuntu 16.04.2)
Then how to install is described here(remember my note 1)
Well, if you already installed amd-gpu-pro driver,as title suggest it,really we need to know if installation pass without errors ...
So really we need to see output of this command,(to see IF amdgpu-pro is really installed)as answer on this post(please) when you typed in terminal
dpkg -l amdgpu-pro
As amdgpu and amdgpu-pro are NOT same drivers!
Well,i can write also how to install amdgpu (without pro sufix) driver,but in this case of notebook and 16.04 LTS version of Ubuntu i recommend that amdgpu-pro driver((partly) closed source AFIK),even installation is more complicated for some people,as in this case involve use of terminal,what is not needed for using amdgpu without "pro" sufix driver(open source)as is built in ubuntu kernel,even updating is possible without using terminal,and as i know even if person wanna use non ubuntu kernel,or build kernel, amdgpu open source driver can be installed on one click,in any case,what is nice surprise how far open source drivers came.
Also to be noted perfomace in games amdgpu and amdgpu-pro are more less same.(one is better in some,other in other ones..)
So lets see output of that command...