What is your ambient temperature? Idle tempes should be no more than 10ºC above ambient temperature, so if your ambient temperature is 22ºC, then there may be an issue but if ambient temperature is say 30ºC, then you're fine. Idle temperature is not a good way to measure cooling performance as temperature sensors are relatively inaccurate at low temperatures compared to high temps. Stress test your CPU for 10 minutes at 100% load using Prime95 v26.6 small FFT's. Your average temperature over these 10 minutes should be less than 65ºC or 43ºC above ambient temperature.