CPU Cooling Test Configuration

The standard test bed for cooling tests uses an EVGA NVIDIA 680i SLI motherboard. This is primarily based on the consistent test results on this board and the excellent NVIDIA Monitor temperature measurement utility, which is part of the nTune program. The 680i chipset is also one of the better options for socket 775 CPU overclocking, and it provides great flexibility in our standard cooler tests which overclock to the failure limit with each cooler tested.


NVIDIA Monitor has a drop-down pane for temperature measurement which reports CPU, System, and GPU results. Reviews at this point will concentrate primarily on CPU temperature. In addition to the real-time temperature measurement, NVIDIA Monitor also has a logging feature which can record temperature to a file in standard increments (we selected every 4 seconds). This allows recording of temperatures during testing and play back, for example, of stress test results that can then be examined when the stress tests are completed. There is also the handy reference of speeds and voltages in the top pane to confirm the test setup.

NVIDIA Monitor was compared to test results from the Intel TAT (Thermal Analysis Tool). Intel TAT CPU portions do function properly on the EVGA 680i motherboard, but the chipset-specific features do not operate as they should. Idle temperatures in TAT were in line with measured idle temps with NVIDIA Monitor. The CPU stress testing with TAT pushing both cores showed TAT stress temps at 80% CPU usage roughly corresponded to temps reported in our real-world gaming benchmark.

Other components in the cooling test bed are generally the same as those used in our motherboard and memory test bed:

Cooling Performance Test Configuration
Processor Intel Core 2 Duo X6800
(x2, 2.93GHz, 4MB Unified Cache)
RAM 2x1GB Corsair Dominator PC2-8888 (DDR2-1111)
Hard Drive(s) Hitachi 250GB SATA2 enabled (16MB Buffer)
Video Card 1 x EVGA 7900GTX - All Standard Tests
Platform Drivers NVIDIA 9.53
NVIDIA nTune 5.05.22.00 (1/16/2007)
Video Drivers NVIDIA 93.71
CPU Cooling Cooler Master GeminII
Noctua NF-U12F
ASUS Silent Square Pro
Scythe Ninja Plus Rev. B
OCZ Vindicator
Thermalright Ultra 120 Extreme
Thermalright Ultra 120
Scythe Infinity
Zalman CNS9700
Zalman CNS9500
CoolerMaster Hyper 6+
Vigor Monsoon II Lite
Thermalright MST-9775
Scythe Katana
Tuniq Tower 120
Intel Stock HSF for X6800
Power Supply OCZ PowerStream 520W
Motherboards EVGA nForce 680i SLI (NVIDIA 680i)
Operating System Windows XP Professional SP2
BIOS Award P24 (1/12/2007)

All cooling tests are run with the components mounted in a standard mid-tower case. The idle and stress temperature tests are run with the case closed and standing as it would in most home setups. We do not use auxiliary fans in the test cooling case, except for the Northbridge fan attached to the 680i for overclocking.

Cooler Master provided a small syringe of silver-colored thermal compound without much of a description. Therefore we tested the cooler with our standard premium silver-colored thermal compound. In our experience the thermal compound used makes little to no difference in cooling test results. This is particularly true now that processors ship with a large manufacturer-installed heatspreader. Our only control on thermal compound is that we use the manufacturer-supplied product if they supply a premium product, or a standard high-quality thermal paste if a premium brand is not supplied.

We first tested the stock Intel cooler at standard X6800 speed, measuring the CPU temperature at idle and while the CPU was being stressed. We stressed the CPU by running continuous loops of the Far Cry River demo. The same tests were repeated at the highest stable overclock we could achieve with the stock cooler. Stable in this case meant the ability to handle our Far Cry looping for at least 30 minutes.

The same benchmarks were then run on the cooler under test at stock, highest stock cooler OC speed (3.73GHz), and the highest OC that could be achieved in the same setup with the cooler being tested. This allows measurement of the cooling efficiency of the test unit compared to stock and the improvement in overclocking capabilities, if any, from using the test cooler.

Noise Levels

In addition to cooling efficiency and overclocking abilities, users shopping for CPU cooling solutions may also be interested in the noise levels of the cooling devices they are considering. Noise levels are measured with the case open on its side and are measured using a C.E.M. DT-8850 Sound Level meter. This meter allows accurate sound level measurements from 35b dB to 130 dB with a resolution of 0.1 dB and an accuracy of 1.5 dB. This is sufficient for our needs in these tests, as measurement starts at the level of a relatively quiet room. Our own test room, with all computers and fans turned off, has a noise level of 36.4 dB.

Our procedures for measuring cooling system noise are described on the page reporting measured noise results comparing the stock Intel cooler and recently tested CPU coolers to the Cooler Master Gemini II.

Features and Specifications Fan Configurations
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  • acejj26 - Monday, April 30, 2007 - link

    Page 4...MHz, not GHz
  • AnnihilatorX - Monday, April 30, 2007 - link

    I have a feeling that the size of CPU coolers is directionaly proportional to the trend of global warming

    Don't take this too seriously

    Though the CPU TDPs are relatively constant at ~110W for high end CPUs, the coolers have been more and more elaborate.

  • Wesley Fink - Monday, April 30, 2007 - link

    While TDP (Thermal Design Power or Thermal Design Point)has not varied a great deal recently, the wattage demands of a CPU in overclocking are MUCH higher than at stock speed, and they increase as the overclocking goes up as it dramaticlly does with the current Core 2 Duo processors. The more elaborate cooler designs are to effectively cool in the highest possible overclocking configuration OR to more efficiently cool with less air volume (noise reduction).

    We evaluate coolers using both these criteria - overclocking and relative noise.

    Were we to evaluate coolers on just how well they cooled at rated CPU speed - which we do include in our reviews as "Stock Speed Performance" - our results table would likely look different and our recommendations would also be different.
  • pannivas - Monday, April 30, 2007 - link

    Maybe I haven’t searched hard enough, but until now this cooler is the only cooler that can fit my Zalman HD135 HTPC case 130mm(H) and perform good as well as silently.
  • stromgald - Monday, April 30, 2007 - link

    The Thermalright XP-120 is also a good option for low-profile cases. I saw a review where it performed better than the Thermalright MST-6775, which is in this review, so I think it should be in the ball park of the Gemini II. It's also probably cheaper since it's smaller, and quieter since it only uses one 120mm fan.
  • yacoub - Monday, April 30, 2007 - link

    So basically if you're someone who is looking for a cooler that's average amongst the top aftermarket coolers in prowess, offers a lower height that should fit in just about any case, can mount twin 120mm fans, is practically silent in operation with the right fans, and directs airflow down over the board removing the need for an additional fan to do the that, it could be seen as a good product worth using?
  • Wesley Fink - Monday, April 30, 2007 - link

    If you need a shorter cooler this could be a good choice. It can definitely be "silent" with the right fan(s). It does cool much better than the Intel retail fan.
  • thechucklesstart - Monday, April 30, 2007 - link

    If you set up the fans in a pull configuration if it would increase cooling?

    Most vehicles have a pulling fan on their radiator because it is more efficient than a pushing fan and this situation seems similar.
  • Wesley Fink - Monday, April 30, 2007 - link

    All Cooler Master diagrams and specifications show the fans mounted to blow air down toward the motherboard and components. We tested the fans mounted as Cooler Master specified. The fan wounting direction could be reversed if that is what you choose.
  • BladeVenom - Monday, April 30, 2007 - link

    I think it's would be worth testing. He's not the only one wondering if it might be better that way.

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