A definitive way to clarify what is going on is to bring up Task Manager (Ctrl+Alt+Delete) then head to the performance tab where you will see hardware utilisation graphs, then you can just watch the Memory tab to see how much desktop memory the render is sucking up. For VRAM a secondary monitor (e.g. MSI Afterburner) can be used to see similar utilisation graphs and VRAM usage percentage. This method will clarify what is going on with your computer during the render. You have not shown your 3D view or scene here so I cannot offer too much beyond that, however, make sure your seen is not too heavy for your computer, is there many objects in the scene? Are you using many emission objects for lighting? Are there high-poly meshes being rendered? All these sorts of questions can reveal that the scene may be poorly optimised making it "heavy" i.e. a resource-intensive scene that will suck up much memory in order for it to be rendered. The last thing I will mention is that in File -> User Preferences -> Editing you can set the memory limit in blender to zero, this allows blender to use full memory out of your PC. First try and find out how your hardware is doing during the render, edit the settings and then work on optimising the scene for lower hardware. :)