No Option For Graphics CPU in Render Settings Specs
Windows 10 Pro 64 bit 
Intel i7-4810MQ
Nvidia K3100M
--- [Nvidia Graphics Driver 354.56]
--- [Nvidia nView 146.90] comes with graphics driver above.
Intel HD Graphics 4600
--- [Intel Graphics Driver v10.18.15.4268]
500 GB Crucial SSD
32 GB Kingston 1866 SODIMML RAM
And some other miscellaneous stuff that probably doesn't matter.

Hopefully the image will explain what is happening. 
I am just learning Blender and I am trying to render the monkey head. I set the resolution to 1080p HD TV and then 500%. That should strain the pc right?
Well when I run the render, all 8 CPU cores go through the roof. I am guessing my Video card is not helping with the process.

I think that I have all the settings correct. Why am I not able to select the graphics cpu under the render tab?
PC and Blender Settings
Now you must have Blender Render on that renderer option of yours.
Change it to cycles! Now! Now!

The option box on the render setting will magically appear!



Additional Notes
You may need to make sure the Performance numbers are setup correctly
to make rendering go faster when you are using the GPU. Also beware
that overly bright scene that renders with lots of "firefly" noise
will slow down the render too.


Turn on "Auto Tile Size" in your user preference add on tab.





Here is where you will find the tool on the performance header.