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 DDR2 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 Thermalright Ultra 120 with the Scythe S-Flex fan matched the Tuniq Tower 120 at 3.90GHz. This is the highest stable overclock we have reached on air cooling with this CPU. While we could boot at speeds as high as 3.96GHz, gaming performance was not stable at speeds higher than 3.90GHz. Increasing the CPU voltage also did not increase stability above 3.90GHz.

The best coolers tested have topped out at 3.90GHz. This represents the highest stable overclock that has been achieved with this CPU with air cooling. While we will continue to try to push the better coolers even further than 3.90Ghz, it is fair to conclude that the maximum OC on air with this processor is likely 3.90GHz. The Vigor Monsoon II achieved a higher overclock, but only with Thermal Electric Cooling.

Scaling of Cooling Performance Noise
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  • Wesley Fink - Monday, March 5, 2007 - link

    I have changed the comment to "remove" air.

    A quick glimpse at www.newegg.com shows a number of power supplies with down-facing fans. Examples are the the OCZ GameXStream 700 at http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82..., the Seasonic at http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82..., the Coolermaster 550W http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82..., the Thermaltake 550w at http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82..., the Raidmax at http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82..., and the Enermax at http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82....

    Even at the low end you can find down-facing fans such as the Xion 500W, $29.95 after rebate at http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82..., the house brand Rosewell 400w at http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82..., and the Sparkle 350W at http://www.newegg.com/Product/Product.asp?Item=N82...">http://www.newegg.com/Product/Product.asp?Item=N82....

    Fans which remove air from the CPU area are VERY common and not difficult to find.
  • johnsonx - Tuesday, March 6, 2007 - link

    I think you misunderstood the gist of my comment, but your correction to the article is indeed correct. I was making the point that the bottom fan of a power supply does not BLOW air onto the CPU area, rather it intakes air FROM that area. I'm well aware there are numerous such power supplies available (personally I prefer the ones that have both a bottom and a rear fan, but there are valid points both ways on that debate).

    Sometimes I try to be too creative in my phrasing, thus obfuscating my central point beyond recognition.
  • nilepez - Monday, March 5, 2007 - link

    Since you're reviewing HS, perhaps you need to test them all with the same fan (assuming they take the same fan size). Obviously some come with fans, and you'd want to test with the stock fan, but to make things equal, I think you need to pick a fan (Skythe, Noctua, Panaflo et al.) and test them all with that fan as well. Only then will we know what the best HS is.

    My guess is that Thermalright would still be up there, as they're generally one of the best HS makers (if not the best) out there.
  • Rocket321 - Monday, March 5, 2007 - link

    I would love to see a review of the Ultra 90 you mentioned on page 2. I'm hoping to find something a little lighter than these highend coolers without moving into the budget sector.
  • ADDAvenger - Monday, March 5, 2007 - link

    I'd be interested in a review of that as well
  • orion23 - Monday, March 5, 2007 - link

    Thank you guys for another great review! Great Job!

    It's nice that these coolers are being tested with new setups (C2D) unlike many other sites that choose to test with "old hardware".

    I've always been a fan of the Thermalright Ultra 120 which BTW has kept my 4ghz overclock (E6600) idling @ 28-35 and 50c under load. I tried a Tuniq Tower but the results were @ least 5c higher with the Tuniq!

    Go Thermalright!
  • jonman03 - Tuesday, March 6, 2007 - link

    I have to agree, we get alot of requests for these on our custom systems. Great cooler, looks great in windowed cases. What else could you ask for?

    http://www.plugcomputers.com">Custom Gaming Computers - Plug Computers
  • 1111111 - Monday, March 5, 2007 - link

    quote:

    The problem here is that the mounted fan cannot have a closed mounting post, which is common on many fans. The Thermalright design will only work with open holes and no posts on the fan


    A few minutes with a hacksaw works fine to remove a section of the fan posts. That's what I ended up doing with my Thermalright Ultra-120/Yate Loon D12SL-12.
  • Wesley Fink - Monday, March 5, 2007 - link

    Your suggestion works, and the hack saw works best if you have a vise to hold the fan while you saw. A jigsaw melts the plastic as it moves too fast and creates too much heat for the plastic as it cuts - so it does not work as well.

    HOWEVER, this is a review of a heatsink that does not come with a fan and the special fan post requirements need to be pointed out. Not everyone wants to do shop work on a fan before it will mount on a heatsink.
  • hiepbiz - Monday, March 5, 2007 - link

    I wonder why you tested only the single fan setup. The design of the Ultra 120 definitely suggests a perfect push and pull combo. Also, you didn't mention about the mounting surface of the Ultra 120. It's known that Ultra 120 has a pretty much uneven surface (observable with unaided eyes). I had to lap mine to not only expose the copper surface but also to make the surface flat.
    The reason I brought this up because there are people that don't care about noise and would prefer a very high-performance air-cooling. If the dual setup and a more even mounting surface would help, I would think it would put the Ultra 120 head and shoulder above the Tuniq Tower for these people (that would include me).
    I happened to own both Tuniq and Ultra 120, and I would say I prefer the flexibility the Ultra 120 offers.
    Other than some of the minor points that I've pointed out, I would say that this review (and other recent HSF reviews) is an excellent one. Keep up the good work. BTW, I wonder when you're gonna do a piece on the Coolit Freezone.

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