Performance

Test System

All testing is done at a room temperature of 20°C (68°F), with a 1°C margin of error. The coolers are tested with Turbo, EIST, and C1E enabled, which will allow the CPU to clock down to a low 1.6 GHz while idle, or clock up to proper speeds under stock and overclocked conditions. With the use of XMP, the Intel i7 3960X ES chip I used for testing runs at 3.6 GHz under stock load. Overclocked, the chip is set to 4.1 GHz at 1.225 volts. During all these tests, fans are set to run at 100% in the BIOS, with temperatures being recorded by AIDA64.

The idle test will consist of the CPU sitting idle at the desktop for 15 minutes. This will allow for a stable temperature reading that will be recorded at the end of those 15 minutes.

AIDA64 and its CPU-stability test represent a typical multithreaded user load. It is run for 15 minutes before the highest reading during the test is recorded and taken as the result. This test lets enthusiasts know what temperatures they can expect to see with games and applications.

Prime95 is the multithreaded stress test I will use to find the cooler's temperatures at maximum load. This is done by using the "In-place large FFTs" setting to truly stress the cooler's ability at keeping temperatures in check. The test is run for 15 minutes, and the highest recorded temperature is taken as the result.

Fan noise testing is done at 20%, 50%, and 100% settings, and the dBA level is recorded by a Pyle PSPL25 sound pressure level meter at a distance of 30 cm. Fan RPM results are taken at the same 20%, 50%, and 100% settings.

Idle

During the idle tests, the Noctua NH-U12S proved to be very efficient. It took the top spot in both idle- and overclocked testing. However, dual fans did nothing for cooling at idle.

Typical Load

Once the cooler was placed under typical loads, the NH-U12S began to show its Noctua heritage. The single-fan setup does fairly well at stock clocks, tying the Corsair H90. The dual-fan configuration manages to throttle temps by another 1°C, down to 48°C for third place. The overclocked test shows both configurations slipping back into the middle of the pack. Still, the temps here are as expected for a traditional tower design of this size.

Max Load

The temps after running Prime95 look good as well, but the performance of the Noctua NH-U12S doesn't top the charts. It does well at stock clocks, tying the Phanteks PH-TC12DX that uses two fans. With two fans, the Noctua cooler managed to drop temps by another 1°C, putting it just 2°C behind the best air cooler I have tested to date, the PH-TC14PE. We see the NH-U12S climb back up the chart again with the CPU overclock. Single-fan performance ties the Silverstone Argon AR03 at 66°C. Meanwhile, the Phanteks PH-TC12DX pulls ahead by 1°C. Adding the second fan drops temps by 3°C. This put the Noctua cooler in fifth place while using dual fans, right behind the Corsair H100. The Noctua NH-U12S really is an exceptional cooler for its size.

Fan Noise

The Noctua NH-U12S simply blows me away when it comes to noise levels. At lower fan speeds, this cooler will be impossible to hear over other parts in the average user's case. This cooler is insanely quiet in its default single-fan setup. Noise levels are extremely low even with a second fan. Users can, should they be able to justify the price of a second Noctua fan, look forward to great cooling at nearly silent noise levels.