If anyone is even marginally interested in GPU internals, you'd do yourself a favor by checking out John Owens' UC Davis class on the topic[1]. I once watched the first lecture just to fill an hour and ended up going through the entire course within the span of a week, following up with my own research later on. Superbly interesting.

[1] https://itunes.apple.com/us/itunes-u/graphics-architecture-w...

or on youtube: https://www.youtube.com/playlist?list=PL4A8BA1C3B38CFCA0