I have two case fans: "Scythe Slip Stream 120mm 1,200rpm" as front intake fan and "Scythe Slip Stream 120mm 1,200rpm" as rear exhaust fan. When they both run on full speed, front fan is very noisy while rear fan is quiet. I figured that it's because front fan is obstructed by front panel of my case and lowered its speed by 800rpm using SpeedFan. So now I have front intake fan running 800rpm and rear exhaust fan running 1200 rpm. Is this balance normal or should I replace rear exhaust fan with 800rpm version so they both run 800 rpm?