Have you checked your voltages? There were a few motherboards out there that on Auto where applying to much voltage to these chips, which will definitely create extra heat. Depending on your case, ambient temps, and the game you are playing (some are more CPU intensive) 70 C is likely acceptable, 100 not so much.
I got 5 C drop from lapping my 212 EVO back when I had my 4690K, adding a second fan was worth another 1-2C. Here's a picture after lapping:
I did lap the CPU as well. At least a little. I stopped when I started to get into the copper.