Hi. I had a very similar problem. However, I DO NOT recommend you do what I did. As this will void your warranty. However, I did work for what I wanted. Basically I too was getting upwards of 80c during heavy usage, and hovering around 50 while idle. Regardless of being in Windows or Linux. Also my fan was also always on, and what motivated me to do this fix was at some point the fan began making noises (like it needed to be oiled up). As my warranty had already expired, I ended up removing the fan protection plate, and placing a bit of mineral oil in the mechanism. This solved the sound problem.
However, after carefully inspecting my system, I realized that the cooling ability is just was too inadequate. So I lined up the heat sink and pipes with the outside of the case and drilled my own vent holes. This modification now allows my system to idle around 38c and full load at about 60c. Basically 20 degree drop all around. I was quite surprised at the overall effect. Again I do not recommend this as it does mean physically modifying your case.