Noise

For many enthusiasts upgrading cooling the goal is maximum stable overclock, and they will live with the inconvenience of a louder system. For other users silence is the most important factor, and these users will forgo maximum overclocking if that increases system noise levels.

There are virtually no power supplies that do not include a fan. While Zalman and a few others do make an expensive fanless power supplies, we have not seen a fanless unit larger than 500W, or one that would be used for seriously overclocking a system. With that in mind the noise level of the system with all fans turned off except the power supply was measured. The power supply used for the cooling test bed was the OCZ PowerStream 520, which is one of the quieter of the high performance power supplies.

We have also measured the Corsair 620-watt and Mushkin 650-watt power supplies which are reported to be quieter than the OCZ. Both the Corsair and Mushkin are indeed quieter at idle or start up speed. However, as soon as load testing begins and the PSU fan speed kicks up the measured noise level is almost exactly the same as the OCZ PowerStream 520 watt power supply.

We are currently in the process of evaluating "quieter" power supplies for an update to our cooler test bed. We will make changes to that test bed as soon as we are confident in the noise measurements and test procedures with a variable speed quiet PSU. We plan to evaluate additional power supplies and configurations in our upcoming 120mm fan roundup, at which point we will complete the transition to a revised and lower noise cooler test bed.

The noise level of the power supply was 38.3 dB from 24" (61cm) and 47 dB from 6" (152mm). The measured noise level of the test room is 36.4 dB, which would be considered a relatively quiet room with a noise floor slightly below the OCZ PowerStream 520 PSU.

We measured noise levels with the Thermaltake MaxOrb and the Scythe Andy Samurai Master with the stock Scythe fan at its single speed and the embedded MaxOrb fan at Low and High speeds. Results were then compared to the other coolers/fans tested in this category. Measured noise levels in this chart should be considered worst case. Measurements were taken with an open side of a mid tower case 6" and 24" from the HSF. Real world would be a completely closed case resulting in a further reduction in noise.

Noise Level - 6

Noise Level - 24


The measured noise levels at 6" and 24" are below the system noise floor with the quiet Scythe fan on the Andy Samurai Master. The Thermaltake actually specifies even lower noise levels than the Scythe, but at both low and high noise it was above the 24" noise floor at 40.7dbA at low speed and 45.8dbA at high speed. The MaxOrb fan is definitely audible, but the noise is not particularly irritating in frequency. If you are very sensitive to noise you should be aware you will likely hear the MaxOrb fan with an open case.

At the 6" measurement the MaxOrb was below the noise floor at low speed, and significantly above the noise floor of 47dbA at high speed with a measured 52.5dbA. The Tuniq Tower 120 on high, the Zalman 9700 on high, and the Monsoon II Lite stressed were noisier than this, but this is still one of our highest measurements. Again the noise frequencies are well placed and not particularly irritating as there is none of the high-pitched whine that some fans generate, but the MaxOrb is definitely not silent.

Overclocking Conclusion
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  • lopri - Tuesday, June 5, 2007 - link

    I've always thought the benefit of the blowing-down design is that it 'moves' hot air around MOSFET/VRM/NB area better, therefore contributing to long-term (be it hours or years) stability. I haven't seen an argument that these blowing down HSFs let a CPU clock better than the top offerings from L-shaped design for 30 min. gaming session. (It actually explains a lot other things because up to this date I assumed the load temps were measured under 100% of load - for both cores.)

    Question for Wesley: Could you confirm how much stress the CPU is taking with your test scenario? Maybe using percentage. (like 50%, 60%, etc.)

    Another issue with the Wesley's conclusion is that he forgets the boards built on NF6 chipsets are probably the only boards that come equipped with NB fans. If you look around, vast majority of LGA775 boards don't have a NB fan. As a matter of fact I don't think I remember any 975X/P965 board that has a NB fan. And in AT's own motherboard reviews, I often read statements like "In order to maintain stability, additional airflow was required for the board's MCH...". And these L-shaped HSFs don't provide that required airflow for the MCH.

    I do think there is an agreement among enthusiasts that these L-shaped HSF are better for higher CPU overclocking and/or lower CPU temperatures. But the question is, are you comfortable with VRM that reaches 100C+ for an extended period? How about the board's northbridge that goes beyond 50~100C depending on chipsets? As a matter of fact, the NB of the motherboard that is used on this very review is capable of reaching 100C without overclocking, unless the supplied 'optional' fan is used. (in other words, that 'optional' fan isn't really an option but a must, irrespective of overclocking - if you want to keep the board for more than just a few months)

    In my opinion, the conclusion of this article is severely misleading from many angles. Also my experience disagrees with Wesley's finding that higher RPM fans didn't change the performance of Scythe Andy heatsink, but that's a different issue, I guess.
  • Wesley Fink - Tuesday, June 5, 2007 - link

    As stated on p.4, CPU Colling Test Configuration, "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."
  • redeyedrob - Monday, June 4, 2007 - link

    Be interesting to see a comparison of Northbridge temps between the horizontal and vertical coolers, maybe even a comparison of max FSB speeds resulting from any potential difference in max NB voltages / stability between the 2 cooler types.

    I have an E660 @ 2.4 - 2.8 GHz with an Ultra 120 Extreme which idles at 30 degrees (almost certainly due to the terrible curvature on the base, need to lap) but the NB is idling at 44 degrees.
  • SurJector - Monday, June 4, 2007 - link

    From 3.83GHz to 3.90GHz is 1.83%
    From 3.83GHz to 3.96GHz is 3.39%
    Apart for bragging rights, is anybody able to tell the difference ?
  • Wesley Fink - Monday, June 4, 2007 - link

    As explained in our very first cooler review with Core 2 Duo, the Intel stock fan can do a 3.73GHz overclcok. That is why that is the baseline. If a cooler can't outperform the Intel stock cooler then why should you buy it? If this suggests it doean't make sense to go for more than the excellent Intel retail cooler then we can appreciate your thinking.

    However, this is just one component of cooler perfromance, and you should also look at the cooling efficiency in our cooler tests. The Thermalright Ultra 120 eXtreme with an S-Flex fan under LOAD at 3.73GHz cooled to 43C compared to the Intel at 71C. That's a 40% or 65% improvement in cooling perfroamnce depending on what you consider the baseline.
  • SurJector - Tuesday, June 5, 2007 - link

    The temperature difference (43C against 71C) is indeed important. I feel much better with a cooler CPU.

    The point is when one says "cooler A allows the CPU to reach 3960MHz while cooler B goes only to 3830 thus cooler A is much better". I think it is not much better, it is a little bit better but those 3.4% do not justify any price difference. What is the margin of error of that measure ? Isn't it higher than 3.4% ?

    28C difference do justify a price difference.
    10dB as well.
  • Martimus - Monday, June 4, 2007 - link

    The biggest problem with blowing air back down onto your chip is that you are blowing ht HOT air back onto the component you are trying to cool. It would make a WHOLE LOT MORE SENSE to turn the fan around and blow the air away from the component. This would cause the same amount of airflow through the heatsink, and even cause the same air to be cool the other components on the MB except it wouldn't have been heated by the heatsink first. I can't understand why the manufacturer would suggest blowing the air towards the chip and not away from it. It goes against common sense.
  • strikeback03 - Tuesday, June 5, 2007 - link

    Depends how warm the motherboard components in question are. If component X is at 50*C and the air around it is stagnant, then that air will quickly heat up and the component will get warmer. Since the exhaust air from the CPU heatsink does not get warmed much, you get a flow of air around component X which is a constant temperature and typically much less than 50*C. If your motherboard components are hardly above ambient, or you have ambient air forced across the motherboard from some other source, then the air off the CPU HSF could cause components to warm up, and a down-facing fan would be a bad idea.

    To whoever reoriented their heatsink: Was the fan flipped in place? Moved to the other side of the heatsink? Any difference in noise? I have noticed some fans are louder depending on which side has a grill or fins nearby.
  • Martimus - Wednesday, June 6, 2007 - link

    You could just turn the fan around and blow it away from the component. It would give the exact same airflow as if it was pointed toward the component, except in the opposite direction. This would also avaoid the problem of blowing hot air back onto the component.
  • strikeback03 - Thursday, June 7, 2007 - link

    Unless there was a fan somewhere forcing air across the motherboard for the CPU fan to remove, it is doubtful the outward-facing fan would move nearly as much air at the motherboard surface. Surface of the motherboard is too crowded with stuff for air to naturally flow nicely across it.

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