Noctua NH-U9S 92mm U-Type Heatsink Review

The Noctua NH-U9S is designed to fit Intel Socket LGA2011 / 1156 / 1155 / 1150 and AMD processors. Here is an overview of the system and testing methodology.

Asus P8Z68 Deluze Gen3 Intel Z68 Chipset
Intel Core i7 2600K (3.5Ghz) Quad Core 4 x 256KB L2 Cache 8MB L3 Cache
Noctua NH-U9S (Single / Dual Fan)
Intel OEM Heatsink

The CPUID System Monitor was used to obtain and record system temperature data and being that this is a quad core processor we need something that will work across all of the cores at once.  For this task we're using a new version of Prime95 (p95v255a) that will allow you to spawn (n) instances to test with.

Editors note: Even though the Windows 7 task manager reported 100% processor usage we could never attain a 100% of the rated heat output as documented by Intel (see below) when using Prime95 as a basis for that heat production. Knowing this we ran the stress test until the maximum temperature was attainted and stabilized.

Other things to consider when judging software induced heat output.
a) Clock throttling by the processor at high temperatures.
b) Normal software isn't designed to produce maximum heat output.
c) Variances of cooling temperature.
d) Variances in CPU load.
e) Inaccuracies in thermal diode readouts.
Of course the list goes on..

Our testing methodology is aimed to provide a real world look into this heatsink given the test system provided.

A C/W rating can quickly be calculated using this formula.

C/W = (CPU temp - Ambient temp)/(Variance(%) * CPU Watts)
Allowed variance for this test = 85%
CPU Watts = 95W

0.32 C/W = (47C - 21C)/(.85(95W))

For this next test the CPU speed was cranked up to 4.7Ghz and the test was re-run.

To calculate a new C/W rating for this test we will need to factor in the increased processor wattage. The formula and constants for this are listed below.

ocC/W = dCPU Watts * (ocMhz / dMhz) * (ocVcore / dVcore)2
ocMhz = 4700
dMhz = 3500
ocVcore = 1.375
dVcore = 1.2
The variance still applies for our C/W calculation
Allowed variance for this test = 85%
CPU Watts = 167W

0.32 C/W = (67C - 21C)/(.85(167W))

In our heatsink and waterblock tests we don't really focus on overall load temperatures but rather how well the product can remove heat given a specified heat load. Since this is a real world testing method we need to take into consideration real world variables and estimate tolerances. This is why we normally only apply 85% of the total wattage output to our heat calculations.

The resulting C/W number is used to rate how efficient a heatsink or waterblock is based on the given heat load. These numbers can be used to determine heat capacity, the larger the difference the less efficient the heatsink is. (aka not good for overclocking)

As our charts show we have a heatsink that can clearly handle more than the system can dish out.  In terms of raw temp the 67c load under overclocking is a little high however when you consider the load temp of the OEM cooler at default speed this is well within tolerance.  The NH-U9S includes hardware for LGA 2011 and while our OC tests show it can handle the 130w+ TDP  there isn’t much room for overclocking.

It should also be noted that we did test this heatsink using all fans spinning under the Asus Turbo PWM fan profile.  This profile is a little more aggressive than the default enabling them to spin up faster under load.  Despite the higher than expected OC load temps the NH-U9S ran extremely quiet at default speed and adding a secondary fan lowered overall load temps by around 4c across the board which is actually quite good for a heatsink of this size.

 Keep in mind these calculations are provided for demonstration purposes only and may not reflect the actual lab tested C/W rating, but we're pretty close.