I have an i7-4770 (one level newer than yours, and without the integrated GPU) and it seldom reaches 50 degrees C.

I have two questions for you:

1) are you forcing overclocking of your CPU? That can cause higher temperatures. Also, CPUs these days tend to underclock when temperatures exceed a certain percentage of their maximum allowed temperature to avoid frying the CPU (maybe the 90 degrees C you are seeing is that point).

2) how long has it been since you opened your computer and vacuumed the dust out.

Also, could there be some combination of GPU settings between the two you have that is adding to the heat? I have heard a lot about the interaction between the Intel HD series of integrated GPUs and discreet GPUs (like your GeForce 650M) and some of the difficulties some users have had, but since I don't have an integrated GPU I have not been following those concerns in sufficient depth to be of any help to you. Other fans here may provide better guidance.

GC3 is a new product and is built for newer CPUs than previous games, including Elemental and, with its wider range of map sizes, larger number of computer opponents, larger number of inhabitable population centers (cities, planets), etc, is more complex and demanding on the CPU processors.