Your max temp (74C) is quite high. When you say you have a Thermaltake CPU cooler, do you mean your CPU heatsink is made by Thermaltake? Or is your case made by Thermaltake? Those are two different things.
I suggest you get the Cooler Master Hyper 212 Plus. 30$, and even with my high (30C) ambient temperature, I still get 40C idle and 60C load with my i5 750 at 3.2 GHz.