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: 2.20V
nForce SPP Voltage: 1.5V
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 Scythe Infinity overclocking was just average in the stock single fan configuration - reaching 3.83GHz with complete stability. However the second fan in a push-pull configuration allowed the Infinity to match the highest overclock on air we have seen with this CPU. At 3.9GHz the Tuniq Tower 120 was still cooler, but the Infinity still managed to hold 3.90GHz with stability during our load testing.


These overclocking results were particularly interesting since we have seen some forum comments that the second cooling fan made little difference on the Infinity. Our results indicate the second cooling fan can make a very significant difference in both cooling and overclocking the Infinity.

The smaller differences others have reported may have been the result of a less demanding test configuration or perhaps it was a result of a better single cooling fan on the tested Infinity. To test this second possibility, a higher RPM and CFM Silverstone fan was mounted on the Infinity as a single fan and the highest overclock was tested. The Infinity with the beefed up fan reached 3.85Ghz - a little higher than the 3.83GHz with the stock fan - with temps about 1C lower than the "silent" fan shipped with the Infinity. Clearly a fan pushing more air improves performance by a small amount, but it still does not match the performance of two "silent" fans in a push-pull arrangement.

Scaling of Cooling Performance Noise
Comments Locked

39 Comments

View All Comments

  • Wesley Fink - Monday, February 26, 2007 - link

    The famous thermal compound review is at http://www.dansdata.com/goop.htm">http://www.dansdata.com/goop.htm. While it is written tongue-in-cheek the test methods are well conceived and there is a terrific discussion of what is significant and what is trivial in testing computer components. After I read the review a while ago I tested every thermal compound I had spent big bucks on and got very similar results.

    I will concede that the more fluid compounds do work a little better when you have tiny contact areas as in the older Socket A AMD - at least initially. But with heatspreaders on all the CPUs these days the thermal grease used makes very little difference as long as it holds up, isn't particualrly conductive, and doesn't dry out. Applying it properly can make a big difference in performance, however.

    Those not from Oz may recall the Men At Work song "Down Under" that makes reference to a "vegemite sandwich". Now you'll understand Vegemite is that brown vegatable spread about the texture of mayonnaise that is uniquely popular in Austalia.
  • DrMrLordX - Tuesday, February 27, 2007 - link

    While I'll generally agree with you, there is at least one TIM that is positively insane that may outperform the usual gunk, and that's Coollaboratory's Liquid Pro (their Metal Pads don't seem to work as well). That stuff will literally dissolve aluminum and otherwise make a terrible mess. It's mostly gallium, indium, and tin I'm told. Strange stuff.

    Others swear by Shin-Etsu X23-7783D as being clearly superior to AS5 and AS Ceramique. I've only seen one benchmark featuring the X23, but it even beat the crazy Liquid Pro in that benchmark.

    Really, it would be more interesting to see benchmarks of the TIMs themselves than anything else. Your current TIM strategy in your heatsink tests is fine by me.
  • BigLan - Monday, February 26, 2007 - link

    I think the toothpaste and vegemite article is on dansdata. (Dan used to do HSF reviews back in the Socket A days and had literally dozens of them all compared.) While toothpaste might work for testing, it does dry out very quickly and so would need to be replaced after a short period of time (probably days.) You could use it in a pinch, but I wouldn't want to try for 3117 overclocks with it!
  • Binkt - Monday, February 26, 2007 - link

    "We have the Thermalright 120 in for review, and we will also be testing the Scythe Ninja Rev. B. Noctua, an Austrian manufacturer of cooling solutions"

    Could you be specific on the model of thermalright 120 that you have in for upcoming tests? I assume that you mean the Ultra-120, since it is the current heavy-hitter from my personal favorite manufacturer.

    Thanks, and keep up the great work!

    PS. Any hope for a look at virtualization performance of current CPU's and platforms? hint: Asrock 775Dual-VSTA vs. more expensive i965 boards vs. AMD VT-enabled platforms ?
  • Wesley Fink - Monday, February 26, 2007 - link

    The cooler is the Thermalright Ultra 120.
  • lopri - Monday, February 26, 2007 - link

    It's got to be Ultra-120. I'd personally rate Tuniq 120, Scythe Infinity, and Ultra-120 as top 3 air coolers today. BTW, what does this article have to do with virtualization??

    To Wesley: Thanks for the article. And I totally agree with your assessment on Infinity's mounting mechanism. It flexes motherboard and makes me uncomfortable to have it in my tower. Also it might not block DIMM slots on the tested motherboard, but I had some difficulties on other boards. (especially if I wanted to make use of any RAM cooling)

    quote:

    However, it is also clear than the current stock Infinity is not quite as good as the original models in reaching very high overclocks.

    Did Infinity go through revisions? If so, what are the differences from original model and the current one?
  • thestain - Monday, February 26, 2007 - link

    Making comparisons based upon 38 dba is not a real test of quietness, try to get your rig a little quieter, maybe shoot for 33-34 so we can see these products spread themselves out more. Have you made any effort to test your test rig to see if the Power supply is making too much racket, in qhixh case replace it with a comparable performing Corsair or Seasonic, and can you turn down the fan slightly on your graphics card??



  • Wesley Fink - Monday, February 26, 2007 - link

    With all computers, monitors, printers, lamps, etc. turned off in our testing romm the ambient noise is 36.4db. Reaching 33 to 34db as a base is therefore not likely. The OCZ 520 is one of the quietest power supplies we have tested. We have also tested with a small basic video card just to see if noise can be lowered further. The result was we had reached the floor of the PS. We also have to unplug the nVidia northbridge fan during noise measurements because it is much louder than the PS, video card fan or most coolers that we have tested.

    There is a place for fanless power supplies, fanless video cards, and coolers that are silent, but for the great bulk of readers we really see little point in testing below the noise floor of the power supply.

    We could do like some other sites and isolate the test board in a sound chamber away from the power supply, but I seriously doubt this is how our readers run their silent PCs. We definitely hear what you are saying, but our noise testing is looking at real-world noise levels. There are other sites that specialize in silence at levels you would more likely find in a noise testing lab.
  • cujo - Monday, February 26, 2007 - link

    you're forgetting a very popular cooler. i'd love to see the results of that vs. these other coolers.

    i would also suggest looking at motherboard/chipset temperatures as most of these tower coolers do nothing for those.
  • DrMrLordX - Tuesday, February 27, 2007 - link

    I'm sure they'll get around to it eventually . . . that or the Big Typhoon VX.

    The article is well-done though, and I'm very glad that you did the dual-fan setup guys. If you look at other tests of the Infinity with dual fans, you'll find that using anything faster than 1200rpm in a push-pull config is really unnecessary. Once you have the second fan going you're getting the best you can get out of the Infinity.

Log in

Don't have an account? Sign up now