Hmm, i really can't tell...
So far, with the stock HSF on my Intel Dual Core E6500 i have 37ºC idle but i haven't look on full load
But a Noctua NH-D14 should perform a lot better than the stock one from Intel. I guess not too much on the idle side but on the full load side.
You could always check if the HSF wasn't placed properly, or poorly adjusted.