|The fan is supposed to run slow or not at all...it's called "Antec Low Noise Technology". It's a feature built into many Antec PSUs. Here's the description:|
"This technology is a new approach that achieves optimum balance between noise reduction and necessary cooling with an advanced temperature response system that outperforms previous solutions. The system constantly monitors the temperature inside the power supply, and then runs the power supply fans at the lowest speed appropriate to load and conditions. Thus it is able to perform much more quietly than standard ATX power supplies or even those with traditional thermally-controlled variable-speed fans."
All it does is monitor the PSU temp. It has nothing to do with the system. While a PSU's fan does assist with case cooling, that's not it's purpose. If your system is running hot, reconfigure your case cooling configuration, not the PSU.
How many case fans do you have & how are they arranged? What's the system & CPU temp - at idle & under load? If your CPU is running hot it's likely that the HSF wasn't installed correctly.