Date:
Tuesday , April 01, 2008
Author:
Marc Adams
Editor:
Kyle Bennett
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Noctua NH-U12P Processor Cooler

Four heatpipes, thirty-six fins, SSO bearings, Vortex Control notches, and psycho-acoustic optimizations...wait just a damn minute. Let's find out if Noctua spent more money on marketing or engineering. It's just a CPU heatsink, right?

continued...

SYSTEM SETUP

All testing of the various heat sinks will occur on our new test bed. This consists of the Asus Maximus Formula paired with none other than the Intel QX9650. You guys asked for quad-core testing and you got the grand daddy of all quad-cores. The video card of choice is the NVIDIA 7900GTX thanks to its dual slot cooling solution and low heat output.

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Test Methods

CPU

When we concluded the first roundup of CPU heat sinks Kyle and I both came to the same conclusion. Software monitoring just isn't going to cut it. We need to step it up the [H]ard way. That is just what we did. We reached out to Intel about using a hardware monitor drilled into the IHS to measure the CPU temperature and wouldn't you know it, this is the exact way Intel tests their own chips. Now we knew we were on the right path. A few weeks later and this is what arrived at my door direct from the Intel laboratories.

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Temperatures for the CPU will be measured using a Sperry Digital 4 Point thermometer. We can also monitor the temperature of the North Bridge through the Asus Probe application. This will let us know if the heat sink provides any additional cooling to other components. Something that becomes more and more important as you overclock.

Now you may be asking why we didn’t just use a quad core CPU and continue monitoring temperatures through software. Take a look at this table. These measurements were recorded using the Intel stock cooler with the CPU at default settings. Core-Temp reports the individual temperature from each core.

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With large discrepancies and variations between programs, this is why we chose hardware monitoring.

GPU

For this article the GPU will be kept at stock speed to keep any excess heat away from the CPU that could impact the results. In 2D mode the 7900GTX under clocks its core to 275MHz which creates very little heat and allows the fan to run at inaudible levels.

Thermal Paste

Noctua's NT-H1 thermal paste was selected as the paste of choice for a few key reasons. Firstly, the thermal paste has been shown to provide excellent thermal conductivity allowing the heat sinks to better do their job. Secondly, there is no observed curing time. That is, performance does not get any better over time. Any curing time could have introduced variables into the equation causing at best dubious results and at worst unreliable ones. Lastly, because we have a special CPU on our hands it requires a compound that is more viscous so not to seep into the channel and run off.

Ambient temperature will be kept at 25C for the duration of the tests and measured with a MicroTemp EXP non-contact infrared thermometer and cross referenced with the Sperry Digital 4 Point thermometer. Any variance greater then 0.2C will halt the testing until temperatures return within spec for fifteen minutes.

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Idle

Idle temperatures will be recorded after a fifteen minute period of inactivity. Any fluctuation during the last sixty seconds will reset the timer for an additional five minutes.

Load

Load temperatures will be recorded after a fifteen minute period of 100% load. To obtain this we will be using Prime95 v25.3. We have previously used Intel's Thermal Analysis Tool (TAT) to create a load on the CPU but this application is not designed for quad-core CPUs. Any fluctuation during the last sixty seconds will reset the timer for an additional five minutes.

Sound

Sound levels will be measured with a Reliability Direct AR824 sound meter from a distance of four feet away. With everything turned off and the room completely silent the meter registered a sound level of 38dB(A). This is a very quiet room where a simple pin drop could be heard. All sound measurements are recorded in the very late evening to further reduce any ambient noise.