In trying to find the actual cause of this event one has to look to any possible weak points in the set up as a whole and if I remember back you have two different types of RAM currently running in the machine. One set is using XMP profiles and one set isn't, I would turn off the xmp and see if it makes a difference.
Heat can also cause this issue to happen with either the cpu or gpu although the temps for the gpu you quote above are ok. Todays gpu's usually run quite warm (70-80c) so don't worry about that. Try reseating the gpu as well.