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.
It may seem that the stock results are a bit on the higher side of average, but there are two things you need to consider here. With 7.5V going through the fan, it was spinning at only 650RPM (dead silent). So, for this cooler to have a result of 52 degrees at this point, I can understand why when it is paired with this fan. In reality, the results are above average, it is just that there are so many coolers in front of it to skew the appearance of these results.
The overclocked results do leave me slightly disappointed with the Mugen 4, but it is still acceptable when you consider all things. One the fan is only at 1400RPM, and still with quiet noise levels. 75 degrees is right in the middle of the scale here, and when considering the prices of what it is leading in this chart, this isn't all that shabby.