SilverStone NT06 Evolution Heatsink Review

The SilverStone NT06 Evolution is designed for all Intel 775 and Athlon64 processors; here is an overview of the system and testing methodology.

DFI LanPartyDK X38 T2R Intel X38 Chipset
Pentium Core 2 Quad Q6600 running at 2.4Ghz
SilverStone SST-NT06
w/ Silverstone 120mm 1200RPM fan – SST
w/ ADDA Corp 120mm 2500RPM fan - ADDA
CoolerMaster Hyper 212
OEM Heatsink

Smart Guardian 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.

In our case we choose 4. 

Editors note: Even though the Windows 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

0.42 C/W = (56C – 22C)/(.85(95W)) 

For this next test the FSB was cranked up to 400Mhz 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 = 3200
dMhz = 2400
ocVcore = 1.44
dVcore = 1.25
The variance still applies for our C/W calculation
Allowed variance for this test = 85%
CPU Watts = 168W

0.41 C/W = (80C – 22C)/(.85(168.1W))

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)

Here we have a heatsink that finally proves our C/W calculations to be accurate.  All too often we find a rather pronounced variance between the default and overclocked speeds which is sometimes good and sometimes bad.  For these tests you’ll see that the resulting C/W numbers are virtually identical which for an aircooler is excellent.  This tells us the NT06 Evolution is working properly and comes with plenty of cooling capacity.  Sadly the downside to our overclocking tests was the 80C load temperature, not exactly processor friendly.

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.