...why the hell does the CPU gets so loaded from just launching a game? From 2% to 80%?
This is actually normal. Some games are more CPU-dependent and some are more GPU-dependent. Even the GPU-dependent ones will still load the CPU pretty heavily, because things like enemy AI and physics and such still require the CPU.
I'm thinking your temp problem is the combination of your ambient temperature and the stock Intel heat sink. The stock Intel cooler has problems controlling temps even when the ambient temps are lower than yours are. To solve the issue you will need to invest in a better cooler.