Scaling of Cooling Performance

Scaling charts plot the performance of a cooler as the overclock is increased. This begins to provide a picture of the areas of most efficient performance for each cooler. It also provides a graphic way to compare performance curves for the various tested coolers. The lower the line for a cooler (representing lower temperatures), the more efficient that cooler is at cooling.

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At 2.93GHz the retail HSF is running at 41C, compared to 30C with the stock Noctua and 29C with the push-pull fans. This is not the best performance seen in our tests at idle, but it is competitive with the top coolers tested so far. This is a delta of 11C. The delta becomes greater as the overclock increases. At 3.73GHz the idle with the retail fan is 56C compared to the Noctua at 42C/39C dual - a delta of 14C/17C dual. While the cooling performance of the Noctua is much better than the Intel retail cooler at idle, it must be said that the Noctua still does not reach the same cooling levels seen in the Thermalrights or Tuniq 120.

Cooling efficiency of the NH-U12F under load conditions was compared to the retail HSF and other recently tested CPU coolers. Load testing can be very revealing of a cooler's efficiency. A basically flat line, particularly from 3.73GHz upward, indicates the cooler is still in its best cooling range. A line that is increasing rapidly indicates a cooler nearing the end of its ability to cool efficiently. Lines which parallel the best coolers over a range of values are showing similar efficiency slopes.

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The Noctua is very efficient in cooling in the 2.93GHz to 3.73GHz overclock range, particularly with push-pull fans. It continues on to a highest overclock of 3.88GHz, which is just short of the 3.90GHz most of the top coolers in our testing have achieved. However, the sharp slope of the line from 3.73GHz to 3.88GHz indicates the Noctua is rapidly losing its ability to cool effectively at these higher overclocks. Compare this, for example, to the lines for the Thermalright Ultra 120 Extreme and the Monsoon II Lite hybrid air/TEC cooler. Both these coolers have very flat stress performance lines as the overclock rises above 3.73GHz, which suggests they are still efficiently cooling and the CPU ran out of overclock ability rather than the cooler reaching the limit of what it could effectively cool.

As stated many times, the overclocking abilities of the CPU will vary at the top, depending on the CPU. This particular CPU does higher FSB speeds than any X6800 we have tested, but the 3.9GHz top speed with the top tier heatpipe towers is pretty average among the X6800 processors we have tested with Tuniq cooling. A few of the other processors tested with the best air coolers reach just over 4 GHz, but the range has been 3.8 to 4.0GHz. Stock cooling generally tops out 200 to 400 MHz lower, depending on the CPU, on the processors tested in our lab.

Cooling at Stock Speed Overclocking
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  • tk11 - Wednesday, April 25, 2007 - link

    Enough with the heat sink reviews. They make something hot, cool... big deal... they're all virtually identical. Please review an interesting or useful technology before we all loose interest in the site.
  • poohbear - Wednesday, April 25, 2007 - link

    lol they're all virtually identical eh? u obviously do NOT overclock.
  • tk11 - Wednesday, April 25, 2007 - link

    Actually I do overclock... by identical I was referring to the lack of innovation. The main differences between these coolers are size and styling, neither of which require technical analysis. Being a long time reader I was simply expressing my lack of interest in the latest series of reviews in hopes that anandtech will return to covering some of the more interesting technologies.
  • LoneWolf15 - Wednesday, April 25, 2007 - link

    Speak for thyself, not others. Plenty of people read these; if you don't, feel free to move on.
  • Jesse3G - Wednesday, April 25, 2007 - link

    I'm amused that you freely speak for others, but presume to restrict the privlege from another? Your post flirts with hypocrisy and the person you addressed brought up a valid opinion.

    Personally I'm surprised at the management decision on this cooling coverage. Why handle one at a time when this topic can clearly be consolidated into a comprehensive discussion of cooling??? A true "round-up" would compile all of these reviews into an inclusive article for each major cooling system category, with Anantech's enclosed suggestions of the best setups available.
  • SurJector - Wednesday, April 25, 2007 - link

    That would be nice to have those noise ratings: how does the stock fan compares with the SilenX and how much more noise the push-pull configuration makes ?

    Thanks for the reviews.
  • Wesley Fink - Wednesday, April 25, 2007 - link

    We did try SilenX with push pull and the noise ratings were still below the system noise floor set by the power supply. Cooling performance was roughly the same as the stock Noctua fans in push-pull and the overclock was not extended, so we saw no reason to pursue it further. The Noctua ultra low noise fan appears to push a lot of air and apparently generates high air pressure compared to some other low noise solutions.
  • puffpio - Wednesday, April 25, 2007 - link

    So then..the ultimate review would probably be these Noctua 120mm fans on an Thermalright Ultra 120 Extreme in a push pull?
  • poohbear - Wednesday, April 25, 2007 - link

    well can u guys bug thermalright for an advance review of their IFX-14? u guys managed to review the TR ultra 120+ early, maybe u can do the same w/ the monstrous IFX-14?
  • Wesley Fink - Friday, April 27, 2007 - link

    Thermalright has just advised us that the Thermalright Ultra-120 eXtreme is in full production. The problem with the mounting plate has been corrected in the release cooler.

    "The 775 bracket issue has been addressed and Ultra-120 eXtreme is now in full production. We think it’s even better than the engineering piece you received back then. Would you be able to verify that if we were to send you the “production” sample with its own packaging and all? I think you’ll be pleased to see the results and the improvements."

    We have a final production sample with improvements on the way. We also have requested an IFX-14 for review.

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