Agreed. 40C is a fair temperature. 65+C is hot for me. If your worried about noise, then set it to a fair speed where it has sufficient airflow for cooling and low enough noise, otherwise if your not noise-worried, raise it to the max.
high temp story: overclocked a slot 1 400Mhz to 600Mhz 50% overclock.. from40c idle to 82C idle... and you can guess the temp when I started benchmarking the computer... amazingly it lived, no bsods, just one restart.. andwhen it restarted the temp was at 88C+ It had 2 small fans that moved probably 10CFM (together)... imstalled a 70mm fan on it (with a bit of modifying) and got the temp down to 50C idle,
Curious: Overclocking?