with the pc on go into the bios and for 10 min or so look at the cpu temp there. if there 35-40c then the cooler is working fine. in windows the low temp will be with nothing loading the system...cpu speed step slwing the cpu and turning the other non needed cores off. gaming and doing other work if the cpu at 50-60c your fine. 70c or higher under load is pushing to where the cpu or the mb will turn off the pc for over heat.