Passive Cooling
In certain extreme cases you may have to deal with a dead fan; or alternatively you are interested in using a certain cooler as a passive cooler. While we are hesitant to recommend any Air cooler for passive cooling, unless the manufacturer has designed it to be one, we all know things break and there is a possibility of ending up with a passively cooled device even if you neither meant nor wanted it to be so! To this end we have devised the following torture test to see how a given cooler will perform in a worst case scenario.
The following test will be PASS/FAIL unless a manufacture specifically states a CPU cooling solution is designed for passive cooling as we feel that do to otherwise would be very disingenuous and down right unfair. If it is designed for passive use we will of course provide hard data on its performance. We believe this is a fair and reasonable compromise between providing you our reader the most information possible, while still being fair and unbiased to the manufacturers.
Any one can create a test which has no possibility of success but that would be a waste of any ones time; this test on the other hand is as tough as we can make it and still have to possibility of success. What makes this test so difficult, is the simple reason that we will be testing in an open bench which has absolutely no external air flow. Even in the most under-cooled cases there is always some air movement, even if the air movement is only coming from the PSU it is still a heck of a lot more than will be afforded a cooler on our open bench. As we stated earlier this is a worst case, scenario where the cooler will have to shed all the heat it can by simple passive radiation!
The first and main part of the test is 15 minutes of prime95 small fft being run at stock speed (2.66GHz) on our Quad Core Intel i7 920. If at anytime the temperature of any of the four cores reaches and stays at 75° C for greater than 10 seconds we will consider this test a FAIL. If a given cooler fails this test a second set of tests will be run using out Q6600 at stock speed (2.4GHz). We will then report our findings in the below chart. Please note: Any Air based CPU cooler which passes the i7 920 test will automatically be given a PASS grade on the cooler running secondary test. To keep things easier to understand the only time we will publish the Q6600 subtest is when a given cooler has failed the main test.
With “active cooling” numbers as bad as the UFO posts is it really any surprise that it fails at passive cooling? All we can say is if you actually plan on using this and its two fans somehow do fail (which is thankfully very unlikely) at least you can rest assured that modern day CPUs will self throttle when dangerous temperatures are reached.
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