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: 11x (Stock 11x)
CPU Strap: 266 (stock) or 333 (overclocked)
CPU voltage: 1.5875V at max overclock
NB Voltage: 1.70V
FSB Voltage: 1.40V
NB Voltage: 1.20V

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 3.33 uses a 333 strap and runs at 10x333, 3.73 runs a 333 strap at 11x339, and 3.90 GHz also uses the 333 strap at 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 Cooler Master Hyper 212 tops out at 3830 MHz with a single fan. This is fairly typical performance for a midrange cooler. Adding a second 120mm fan in a push-pull configuration allows the stable overclock to be pushed to 3.88 GHz. This result is very near the best coolers tested which generally reach around 3.90 GHz. This overclocking performance is excellent for a mid-priced cooler.

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 3.9 GHz top speed with the Thermalright Ultima-90 with 120 fan is pretty average among the X6800 processors we have tested with top air 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.

Scaling of Cooling Performance Conclusion
Comments Locked

21 Comments

View All Comments

  • thoth@cheerful.com - Saturday, September 25, 2010 - link

    choppergirl;

    There is one fatal flaw in your example above. In your suction building you are venting the heat outside the building. and in the blower building you are not. otherwise your examples are correct. In theory the amount of heat transfer is the same for blowing or sucking the air across a heat source with all variables being equal. As one of the previous posters stated to get the variables equal IE the exact amount of air flow.It cost more on the suction set up. Needing a shroud to focus the air flow. This added cost is why manufactures blow the air instead of sucking the air. After all if cost was not one of the driving factors in your system build we would all have decked out Intel hexacore overclocked beast with liquid nitrogen cooling.

Log in

Don't have an account? Sign up now