You said your system temp was at 47 but the CPU was at 37? Perhaps you're straining your CPU cooler because you have a bad airflow in your case. Try running the case w/o the side panel for a bit and see how your CPU fan reacts to that. If it slows down then you may just need to add some new case fans to increase your airflow. Remember, those Video cards create a good deal of heat as well. My case has a fan right over the CPU/Video card that pulls in cool air while the back has two fans pulling how air out. They are quiet case fans, not high RPM, but they move the air efficiently and I get a constant 37 or so while the case temp says 39-40ish unless game, then it raises a couple of degrees.