I'm trying to get started with Blender, and I've gone through a tutorial from Blender Guru. Unfortunately, when I render it, it will only use my CPU, rather than my GPU (660ti) to do any rendering. I've looked at the wiki and changed my preferences for that, and that I could then change the preference for each scene. However, I can't seem to find that anywhere; it was suggested that this might be a setting in the render panel, though I can't find it anywhere (I can find the panel, I just can't find anything other than changing the thread count).

Anything I can do? It's taking me 3 hours to do a full render, and several minutes on each individual frame; which is getting annoying as I'm trying to figure out why some of the frames are getting artifacts on them.