|by 3oh6 | January 21, 2009|
PWM Thermal Testing
PWM Thermal Testing @ Stock Settings
The PWM testing results were gathered at the same time as the CPU temperature results we just looked at. We simply had Everest log the PWM temperatures alongside the CPU temperatures already discussed. The results are interesting though and add a little twist to CPU heat sink performance.
The immediate loser in this group of results is the Thermalright fan in a pull orientation. There just wasn't enough air down low around the CPU socket to remove enough heat from the PWM area to keep up with the others. Moving the fan to a push orientation drastically drops PWM temps with either fan, but the difference is more noticeable with the low RPM Thermalright fan. What really isn't that surprising but still rather impressive, is the fact that the Intel 965 heat sink beat out both push/pull setups. The Intel heat sink is actually a good design, it just doesn't have a high heat load capability, and it generates an awful whine in order to perform at all.
All fan configurations show a relatively similar and consistent pattern through the thermal testing with the only real temperature volatility showing up with the pull setups. This PWM testing has clearly demonstrated that the Thermalright Ultra-120, in this EVGA X58 SLI setup with no additional fans, clearly isn't best friends with the pull setup. Pushing air through the well designed heat sink appears to create much more airflow down around the PWM and CPU socket area than pulling air through. This makes perfect sense given the baffles of the heat sink fins and the configuration we used in testing.
PWM Thermal Testing @ OC Settings
We will now see how these setups handled a much hotter PWM area. At the voltages and CPU frequencies we performed this testing at, the PWM cooling of all the setups will definitely be challenged.
The first thing we looked at was whether the Thermalright/Vantec stealth setup was going to outperform the higher RPM ADDA setup and not only in the push/pull setup, but also the push setup, the Thermalright included fan shows lower PWM temperatures. We are starting to believe that there is some sort of physics property at play here, or our test setup/methodology isn't quite 100% equal. We tried our best to have the fans located in exactly the same location on the heat sink for each setup but inevitably that might not have been the case. Because of this we won't really dwell on which is the best setup, rather, what is the best configuration. Clearly the push/pull configuration wins out, hands down, but the push configurations with both the low and high RPM fans really did perform admirably.
We can see that the Intel stock cooler really recovers from heat load the best so a little trick for EVGA X58 SLI owners using the Thermalright Ultra-120 eXtreme might be to run a dual low RPM push/pull setup with the fan pulling air through the heat sink sitting as low as the mounting screws will allow. This should provide not only the best cooling for the CPU, but more than adequate cooling for the PWM as well.
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