I have a fractal r4 and I'm looking for two quiet fans to add to the case to get the most airflow with as little noise as possible. I'm going to put the stock fans in the front at 5v so I need one for the back and top. For the top i was thinking a corsair af140. how are they when it comes to air flow noise? Ill probably run it at 7v. does anyone know what RPM they run at when set to 7v and if they will start at 5v? For the back I'm considering a thermalright Ty-140 and using the pwm feature. Would this work well as a case fan or would another corsair be more ideal? As for temps my 3770k idles around 26-31C. However the temps on the cores fluctuate in that range every second or so. If I open a small program like Microsoft security essential temps will jump to mid 40s for a second or two then drop back down. Is the fluctuation and temp spikes normal?