Test Results and Analysis

I first checked the efficiency of the heatsinks’ native thermal paste. The syringe hasn’t any identifying marks or labels:

I contacted Noctua and received an immediate and “exhaustive” response that “Noctua heatsinks come with a highly efficient silicone-based thermal interface”. Yet the company representative also stressed the fact that the Noctua coolers perform the best when used with Arctic Silver 5. Anyway, the native thermal paste included with the heatsinks is quite enough and I used it in my tests.

The Noctua NH-U12 and the Thermaltake Big Typhoon (also with the above-mentioned Thermaltake Thunderblade A1926 fan) were tested at two fan speeds: a quiet 1280rpm and a maximum 2000rpm. The Noctua NH-U09 was tested with a 92mm fan at a very quiet (almost silent) speed of 1600rpm and at the maximum speed of 2000rpm. I made pauses of about 30-40 minutes between the test cycles for the temperature to stabilize.

Let’s first look at the results I’ve got in a closed, but well-ventilated system case:

So it is clear there’s now one cooler more which is better than Thermaltake’s Big Typhoon. To be exact, the Noctua NH-U12 keeps the CPU cooler by 2°C than the Big Typhoon at both the min and max speed of the fan under the S&M load. The CPU temperature goes down by 4°C with both these coolers when the fan speed is increased to the maximum. However, this is only true for S&M (or Sado-Maso as it is sometimes referred to by overclockersJ) whereas the temperature difference under the Super PI load is a mere 1°C.

You may be wondering why buy a super-cooler at all if the ordinary boxed cooler from AMD can cope with a processor overclocked to 2.7GHz at increased voltage and running S&M? Well, just look how fast its fan is! The fan is too noisy at 4700rpm, you will hardly want to be near this computer for long. Even the noisiest of the fans I’ve tested today (Thermaltake’s Thunderblade A1926) is not as hard on your ears at its 2000rpm as the boxed cooler’s fan is.

As for the junior NH-U9 model, it is not far behind the Noctua NH-U12 in the quiet operating modes, but at the max fan speed there is a difference of 5°C between them. The Noctua NH-U9 seems to ask for a faster fan since the 92mm is less noisy at its maximum speed of 2000rpm than a 120mm fan at the same speed. In other words, the junior model loses in terms of performance but wins in terms of noiselessness under such test conditions. Still I would rather judge a cooler by its efficiency in quiet modes which are more relevant for practical use.

Now I’m going to eliminate the influence of the system case on the test results and see what happens on an open testbed. In this test I put two 120mm Sharkoon Luminous Blue LED fans (1000rpm, 21dBA) on both sides of the Noctua NH-U12 heatsink for driving air in and out.

Note that neither of the Noctua coolers needs a high-speed fan to pass the S&M test on an open testbed. It’s only in SuperPI that the higher fan speed improves the temperature; there is no such difference under S&M. So I can’t but recall the claim of Noctua that its coolers don’t need a high-speed fan – this is indeed so! The Thermaltake Big Typhoon, on the contrary, reacted eagerly to the higher fan speed. Its efficiency got 2°C higher and it became one of the leaders in the open testbed tests.

My attempt to use two 120mm fans on the Noctua NH-U12 (one for driving air in and one for driving it out) proved to be a failure. The fans seem to have been hindering one another rather than helping.

Acknowledging the highest efficiency of CPU cooling, I still can’t pass by one drawback. The temperature reported by the PWM sensor was always higher in my tests of the Noctua coolers than with the Thermaltake Big Typhoon; it is even higher than the CPU Sensor showings with the NH-U9. This is expectable since the Big Typhoon directs its air stream towards the mainboard’s PCB while the Noctua coolers, in parallel to it.