Overclocking

As cooling solutions do a better job of keeping the CPU at a lower temperature, it is reasonable to expect the overclocking capabilities of the CPU will increase. In each test of a cooler we measure the highest stable overclock of a standard X6800 processor under the following conditions:

CPU Multiplier: 14x (Stock 11x)
CPU voltage: 1.5875V
FSB Voltage: 1.30V
Memory Voltage: 1.90V
nForce SPP Voltage: 1.35V
nForce MCP Voltage: 1.7V
HT nForce SPP <-> MCP:
Auto

Memory is set to Auto timings on the 680i and memory speed is linked to the FSB for the overclocking tests. This removes memory as any kind of impediment to the maximum stable overclock. Linked settings on the 680i are a 1066FSB to a memory speed of DDR2-800. As FSB is raised the linked memory speed increases in proportion. The same processor is used in all cooling tests to ensure comparable results.

Highest Stable Overclock (MHz)

The OCZ Vindicator with the stock fan could only reach 3.80GHz overclock with stability. This result is average to below average among the tested heatpipe towers. However a change to the 72 CFM 14 dB-A SilenX IXTREMA 120 allowed us to push the overclock to 3.90GHz with complete stability. This matches the top tier of overclocks achieved by the Tuniq Tower 120, Thermalright Ultra 120/Scythe SFLEX, Cooler Master Hyper 6+, and Scythe Infinity with dual push-pull fans.

The only air cooler that has reached higher than 3.90GHz is the Thermalright Ultra 120 Extreme, which was featured at CeBIT. We managed 3.94GHz with that top air cooler. The hybrid TEC/air Monsoon II Lite reached 3.96GHz in benchmarking, but that cooler combines active TEC cooling with passive air cooling and would be expected to reach higher overclocks than an air-only solution

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.

We measured noise levels with the OCZ Vindicator with both stock and SilenX IXTREMA fans under both load and idle conditions. As might be expected with fans with noise ratings of 18.5 dB-A and 14 dB-A, the measured noise was below our system noise floor at both 6" and 24" positions above the open side of our system case.

There are virtually no power supplies that do not have a fan. While Zalman and a few others do make an expensive fanless power supply, 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 and the measured noise level is almost exactly the same as the OCZ PowerStream 520 watt power supply. In keeping with our "real world" philosophy of noise, we consider the PSU load noise to be the more realistic noise level of power supplies. We do plan to evaluate additional power supplies and configurations in our upcoming 120mm fan roundup, but we will tilt to real world rather than procedures that test fans on foam blocks or hard drive noise with their "noisy" side pointed toward a foam block.

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.

Noise Level - 6

Noise Level - 24

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.

Any 120mm fan should be mountable on the OCZ Vindicator. The fan clips connect to the outside mount hole, which means both open post and the more common closed post fans will work properly. The stock OCZ fan is closed post and the SilenX is open post. This means the SilenX will work on any cooler we have reviewed thus far - including the Thermalright Ultra 120 and Ultra 120 Extreme.

Scaling of Cooling Performance Final Words
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  • Wesley Fink - Thursday, April 5, 2007 - link

    You make a good point, but I remain concerned about introducing additional noise and cooling variables into the test platform with a variable fan speed PS. In flat out gaming every PS I have seen is running at load conditions. However, your suggestions are certainly "real world" and we will definitley evaluate the impact of one of the "silent idle" power supplies on our total cooler testing. Our goal is to find ways to lower the ambient noise and sytem noise floor in realistic ways to provide a wider db test range
  • yacoub - Thursday, April 5, 2007 - link

    Yeah exactly. My PC DOESN'T sit at Load settings for its fans. See I actually have them all dynamically controlled by temp and they only spin up when the machine is actually processing heavily enough to warm things up to a level that needs the fans to spin up a bit more to cool effectively.

    I'm starting to think it's more a matter that most folks don't care enough to quiet their PCs down so they don't realize how much nicer it is to have a quiet PC. This would be why they think it's normal to have a PSU making 40db of noise and thus fans can be 36db of noise and they think that's ok.

    My PC (and it's not exactly designed to be totally silent) is inaudible except when I'm gaming or doing heavy work in a program in windows that requires the cpu to load up a lot. I can surf the Internet, type a Word doc, listen to music, or watch a DVD, and it's inaudible unless you put your ear within a foot or two of the case.

    (P150 Antec case, Antec True-Power2.0 450w PSU (recently replaced by a Corsair 520w that has a fan that is a tiny bit more audible), SpeedFan, ATiTool, and good configurations are to thank for that. It's even using the retail cooler on my A64 Venice 3200+ and it's overclocked to 2.4GHz and it's still silent because I have the fan on it throttle down to 40% when it's under 40C, which it is most of the time.)
  • punko - Thursday, April 5, 2007 - link

    For me, my wife watches television in the same room that I have the computer. When I'm gaming I use either very low sound or headphones.

    Noise is an issue, whether at idle, low load, or heavy load.

    If anything, I tend to have the CPU and GPU maxed out when I'm on the computer, so the "real world" testing of a complete system underload is the most important sound rating. Idle? don't care, that means I'm not in the room.

    What I would love to see is a general guide for those of us planning to build a new rig, and get an idea of what is available in terms of major components for building a quiet (not silent) PC. I am more than well aware that there are specialist sites that do component by component reviews, but I am more interested in the "real world" knowledge of people that assemble and use hundreds of components in various configurations.

    Articles like this one help, because the focus the attention on a particular component as part of an overall system.
  • yacoub - Thursday, April 5, 2007 - link

    oh and by "only spin up" i mean "spin up from the level I have them throttled down to" not "spin up from stopped". You never want to throttle fans down to where they stop while the system is on, because there's always the danger they won't spin back up.
  • asdfqwertyuiop - Thursday, April 5, 2007 - link

    This article is poor. The SilenX claims are just false, and parroting their marketing BS without adequate testing is unsatisifactory. There are about a dozen fans, including the stock Intel one, all on the same db rating. So in other words, testing was insufficient to establish whether or not the fans are quieter than even the bog-standard Intel one.

    Accepting SilenX's BS that their fan achieves dramatically more airflow with less noise than anything else available shows excessive credulity.

    Aside, what's with tech firms and the product names that sound like they are aimed at 13-year olds? Vindicator??? This is a heatsink, not an assault weapon.
  • tomoyo - Thursday, April 5, 2007 - link

    As stated by quotes from a silentpcreview reader here - http://www.silentpcreview.com/forums/viewtopic.php...">http://www.silentpcreview.com/forums/viewtopic.php...

    There's so many inaccurate and incorrect commentary in this review that it's utterly amazing it was ever posted. It's obvious the heatsink was designed by scythe and relabeled by OCZ, that's nothing terrible to say since tons of brand names are made by different companies. I'm MOST disgusted by the blatant love of Silenx fans when their specifications on their fans are 100% WRONG. It is physically impossible for their fans to be as quiet as they say, which means they're purely and utterly liars. A company that lies should not be praised like anandtech is doing. I'm surprised they are not using a quiet nmb-panaflo, nexus, or other good fan out there.
    And the OCZ powerstream is certainly not one of the quieter power supplies out there. A better comparison psu would be something like a Seasonic or Corsair.
    There's plenty of other issues with the writing quality here, but I think these are the most blatant.
  • amdlive - Thursday, April 5, 2007 - link

    quote:

    I'm MOST disgusted by the blatant love of Silenx fans when their specifications on their fans are 100% WRONG.


    What is the true specifications of the fan utilized in this article? If no the specs listed are 100% wrong, then provide the real world results you have. We are waiting and by the way, post a link to your last review.
  • amdlive - Thursday, April 5, 2007 - link


    quote:

    I'm MOST disgusted by the blatant love of Silenx fans when their specifications on their fans are 100% WRONG.



    What is the true specifications of the fan utilized in this article? If you know the specs listed are 100% wrong, then provide the real world results you have. We are waiting and by the way, post a link to your last review.
  • goinginstyle - Thursday, April 5, 2007 - link

    Silent PC Reviews are a total joke. They in no way simulate conditions inside, near, or even remotely in plain sight of a PC. Most of the members over there are elitist wannabes who drink the Chin Kool-Aid and then march off like ants to spread the gospel of lies that are the SPCR test results. Most of their articles are contradictory once you really read them and the computer equipment they use is several generations old. They are not even using equipment that most of us have bought in the last two years and to even consider a P4 and 6800GT as components that stress a power supply is just laughable. The site is one big cluster "F" with most of the recommendations going to their sponsor list. I could not believe some of the asinine comments posted in that topic. Hopefully they wake up and smell the $h!t that is spewing from the writers over there.

    My issues with the cooling reviews here are the noise levels in the room. They really need to be around 26 to 30dBA to properly test most components in your "real world" test routines. There are a lot of people who probably have rooms at home in that noise range along with components whose base noise levels fall in the same category. I would also like to see how well the units fit on the top three or four selling motherboards along with some power supply reviews.
  • Wesley Fink - Thursday, April 5, 2007 - link

    According to a Noise article at SPCR 26 to 30db is the noise level of a "quiet bedroom at night". 35 to 45 db - our ambient noise is 36db - is the noise level of a "Quiet office or library; Typical PC Subdued". The complete chart is in comments below. We hope to lower noise a bit in a reworked test bed but we are not confident we can get below 30db consisitently.

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