I have a Dell Inspiorn 15r 7520 and I get 17FPS on the menu screen in CSGO and 1 or 2 fps in the game(lowest settings) although net_graph says its 17fps. When I run on integrated graphics (HD 4000) I get 50fps. I've just updated the drivers from the dell website and everything is set to high performance. What could the problem be?
Temperature, or simple driver issues may kill it. Have you reloaded this thing? if so check to make sure you installed the mainboard drivers first before loading the video drivers, and NEVER allow windows to load them for you. (I have a blog on that)