The Test System and Thermal Results
Testing for the CPU coolers is done with the use of RealTemp to ascertain temperatures, Intel Burn Test to deliver the load to the CPU and CPU-Z to verify the CPU speed and the voltage being used in Windows. All of the testing is done with an ambient temperature of 24.5-25°C and humidity is maintained to 35% sometimes less.
For the "stock" runs, it's more of a plug and play setup where the PWM of the motherboard is in control of the fans speeds for both the idle and load results. Speed Step is active and the processor idles at 1600 MHz and loads at 3500 MHz for the stock settings. I also set the memory to run at 1600 MHz for stock. As for the overclocked runs, I load the CPU at 4.5 GHz and idle results are obtained with 7.5V to the fans while the load run is set to deliver 12V to the fans. This allows me to gauge the lowest and highest fan ratings for my charts.
You will also see that the charts have been slightly adjusted. From now on I will mention the idle temperatures if there is something worth noting other than an average of twenty-five to twenty-seven degrees as the PWM controls and SpeedStep allow for almost ambient results in most instances. What you are now getting is a stock speed loaded temperature chart and an overclocked loaded temperature chart. To clean up the audio results, I also removed all of the fans that aren't on the thermal charts. If you want to compare those results to new coolers, the old chart is still available in the older reviews.
With a single fan cooling the tower, at stock clocks, the NH-U12S delivered a temperature average of 51 degrees, which is only four degrees warmer than the best air cooler in this chart. With dual fans on the tower, I was able to lessen the heat by only one degree at this level of testing, delivering the 50 degree result.
Once we turned the overclock on and allowed things to stew in their own juices for a while, you can see that the NH-U12S falls to seven degrees behind the best air cooler showing 75 degrees with just one fan. If you wish to spend the extra $20 - $25 dollars for a second NF-F12 PWM fan, you can see you get two degrees of improvement over the single fan configuration.