Scaling of Cooling Performance

While the cooling performance of both the Xigmatek and Evercool were unspectacular at stock speeds, the performance scaling charts tell an interesting story. To be as fair as possible, given the capabilities and limitations of both coolers all cooling tests were run with the Evercool fan at the highest speed. The Xigmatek was run with fan speed on automatic to test what is happening to auto fan speeds.

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At 2.93GHz the retail HSF is running at 41C, compared to 31C with the Xigmatek and 34C with Evercool. This is a delta of 10C for the AIO and 7C for the Evercool. The delta becomes greater as the overclock increases. At 3.73GHz the idle with the retail fan is 56C compared to the AIO at 42C - a delta of 14C. Similarly the Evercool delta of 7C at 2.93 increases to 13C at 3.73. Both self-contained water coolers perform better than Intel stock cooling, but neither comes close to the best air cooling results. The top Thermalright Ultra-120 eXtreme, for example, is at 33C at the same 3.73GHz. However, it is still very interesting that the Xigmatek cools better at idle at all tested speeds than the larger Evercool Silver Knight.

We also need to compare cooling efficiency of the Xigmatek AIO and Evercool Silver Knight under load conditions 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 form 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 indicate that the coolers have similar cooling efficiency.

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The Xigmatek has a very odd stress curve, which is the result of the automatic fan control by the PC. Stress temperature rises rapidly to 61C at 3.73GHz and then drops to 56C at the highest stable speed of 3.83GHz. How is this possible? It appears the fan has not kicked into highest speed at 3.73 GHz, but finally kicks into highest speed by 3.83 GHz. Fan speed change points can be adjusted in the BIOS or in software for optimum performance at the overclocked speeds that you actually run.

The Evercool fan has no auto setting, so all performance tests were run with the fan on high, as already stated. That is the reason the Evercool results under stress progress smoothly from 44 to 60 to 64C. Compared to the Xigmatek, the Evercool is clearly worse in cooling efficiency. Even though it registers 8C cooler under stress at stock speeds this is mostly the result of the Xigmatek operating its fan at lower speeds at the stock CPU setting. By the time the Xigmatek fan is on high at 3.83 GHz, the AIO cools 8C better (56C vs. 64C). This is a clear indication that the Xigmatek is a more efficient cooling solution than the Evercool with both fans at high speed. It is a bonus that the Xigmatek is also quieter at high speed.

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 3.90GHz top speed with the Tuniq 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.

Noise Overclocking
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  • Spanki - Tuesday, July 10, 2007 - link

    Off-topic or not... Woot!! Thanks much - I've always hated those mouse-over links.
  • strikeback03 - Tuesday, July 10, 2007 - link

    I never noticed them until I had to visit the site with IE. Guess AdBlock blocks those dumb underlined links too.
  • asliarun - Tuesday, July 10, 2007 - link

    Thanks, Anand! This helps a great deal. Sorry if my rant sounded too much like a... rant.
  • tuteja1986 - Tuesday, July 10, 2007 - link

    I would like to see thermalright design a cooler like that with better result :) Some has to break the 4Ghz :(
  • Griswold - Tuesday, July 10, 2007 - link

    This technique isnt going to take off no matter who makes it because it defeats the purpose of watercooling by design. Just stick to old fashioned aircooling if you want a somewhat space efficient cooling solution.

    If you want high performance and silence, stick to "real" watercooling with a reasonably sized radiator and fan, not some mini-toy that crams everything in a small box and puts it on top of the CPU like this - and this article proves it.
  • goinginstyle - Tuesday, July 10, 2007 - link

    I think the air cooling reviews are just about played out unless we start seeing AMD results. How well does some of these units already tested work on a 6000+ X2 for example. When will we see reviews with true water cooling setups and products like CoolIt's Freezone? I think a lot people would like to know how well a $100 to $150 water cooling system compares to the top air coolers. How does a custom water cooling solution that might run over $250 work for instance and will your processor do 4.2GHz at acceptable temperature ranges with this type of setup. Otherwise, glad I did not buy one of these self contained hybrid units. It once again appears to be marketing over substance.

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