Core i7 3770K OC at 4600 MHz 1.3 Volts
Now we up the ante. Understand that 1.3V and higher Voltages are the levels where Ivy Bridge processors get into serious problems due to the aforementioned heat-spreader versus TIM design applied solution from Intel. We now set the Core i7 3770K @ 4600 MHz and apply 1.30 volts on the CPU while loading it with 100% stress for a full Prime95 run on all available CPU threads.
Core i7 3770K OC At 4600 MHz 1.3 Volts - IDLE
Below, you can see the IDLE results with the Core i7 clocked at 3770K @ 4600 GHz with 1.30 volts on the CPU. Again, the results are the IDLE temperatures thus you are on your desktop doing nothing.
Core i7 3770K OC At 4600 MHz 1.3 Volts - LOAD
Now we'll be testing the temperatures under stress. If we set the overclock at 4600 MHz and configure CPU Voltage at 1.3V, these are the results.
So for the NH-15D the temps rise above and beyond 70 Degrees C, even with one fan being used the overall temperatures might be very high, but acceptable. The fact remains that very few coolers and kits can actually manage a Core i7 3770K @ 1.3+ Volts / 4600+ MHz temperature wise, but with two fans I'd be comfortable running this overclock. And remember... this cooling level remains silent as well.