Overclocking

As cooling solutions do a better job of keeping the CPU at a lower temperature, then 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: 11x (Stock 11x)
CPU Strap: 266 or 333
CPU voltage: 1.5875V at Max overclock
FSB Voltage: 1.40V

Memory is set to Auto timings on the P35. This removes memory as any kind of impediment to the maximum stable overclock. As FSB is raised the linked memory speed increases in proportion. For this reason memory speed is maintained as close as possible to CPU strap settings to prevent memory becoming an issue in CPU testing. This means 3.33GHz uses a 333 strap and runs 10x333, 3.73GHz runs a 333 strap and runs 11x339, and 3.90GHz is 333 strap and 354x11. The stock speed test is 266 strap and 11x266. We may move in the future to a 3.0GHz stock speed with a 333 strap and 9x333 settings for complete consistency, but since we are not measuring raw computer performance in our cooling benchmarking this becomes a moot point. The same processor is used in all cooling tests to ensure comparable results.

Highest Stable Overclock (MHz)

The OCZ Vendetta tops out at 3870MHz - near the top of tested air coolers. This matches the Thermalright Ultima-90 when it is running a 90mm fan, but it does not quite reach the 3.90 to 3.94GHz of the top coolers tested. However, for around $30 the OCZ Vendetta is able to match the best overclock that could be achieved with entry level water cooling with the Corsair Nautilus 500 or the Swiftech H2O 120 Compact. That is pretty impressive performance for a cooler aimed at midrange air. To be fair the operating temperatures across the speed range for the OCZ Vendetta are generally not as good as the water cooling kits, but the temps are still in the safe range for the X6800 CPU.

The Scythe Kama Cross is more like an Intel retail cooler on steroids (admittedly a light dose), reaching 3.80GHz with the stock 100mm fan and 3.83GHz with the 120mm fan. With the starting price of the Kama Cross actually being higher than the Vendetta, it is difficult to get excited about these overclocking results.

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 Thermalright Ultima-90 with 120mm fan is pretty average among the X6800 processors we have tested. A few of the other processors tested with the best air coolers reach just over 4GHz, 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.

Scaling of Cooling Performance Final Words
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  • strikeback03 - Thursday, October 4, 2007 - link

    should be better, but fitting them would be a problem as they would have to be really thin. Plus small fans are usually loud. Best way to make this cooler worth anything would probably be a shroud to block air from heading straight out the bottom or to the sides.
  • DrMrLordX - Monday, October 1, 2007 - link

    Were it not for the noise on the Vendetta, I'd say it would be entirely preferable to the ever-popular Arctic Cooling Freezer HSFs. At that price point, with that performance, the only reason I could see going for a Freezer 7 Pro would be the noise were I sensitive to that sort of thing.

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