{"id":268121,"date":"2025-12-05T09:00:52","date_gmt":"2025-12-05T08:00:52","guid":{"rendered":"https:\/\/www.hwcooling.net\/?p=268121\/"},"modified":"2025-12-06T22:53:42","modified_gmt":"2025-12-06T21:53:42","slug":"beware-1-a-fan-headers-can-be-too-weak","status":"publish","type":"post","link":"https:\/\/www.hwcooling.net\/en\/beware-1-a-fan-headers-can-be-too-weak\/","title":{"rendered":"Beware: 1 A fan headers can be too weak"},"content":{"rendered":"\n

Multiple fans connected to a single header may exceed the capabilities of your motherboard (or potentially a fan hub). This is due to a higher current draw than the maximum rating. We’ll analyze when and under what circumstances you should be cautious in this article. The threat of permanent device damage is quite real, but it’s fairly simple to safely prevent it. So, let’s take a look at it.<\/p>\n

With a higher number of fans, not only does airflow (and thus cooling performance) increase, but so does power consumption. Its value is also decisive for fan headers. These have a recommended limit of one ampere, which a single fan usually doesn’t exceed. However, if you connect multiple fans to one header, you’re already above one ampere. This is the typical situation when one fan is daisy-chained to another (whether on liquid cooler radiators or at the front of PC cases) and ultimately a single cable leads to one header. But with three fans, there are three motors. And with faster fans, the draw can exceed 1 A.<\/p>\n

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The situation is well illustrated by the graph below (from our standard fan tests<\/a>). It shows power in watts, but based on that, the current draw can be easily derived. You take this power value and divide it by 12 (volts, which is the operating voltage for fans). A draw of one ampere for a trio will be reached by fans with a result of 0.333 A and above. This certainly applies to the Phanteks PH-F120T30<\/a>, Arctic S12038-4K<\/a>, CPS PCCooler F9 R120<\/a>, and Sudokoo Mach120<\/a>. <\/strong>Yes, this is only at maximum speed, and when slowed to lower speeds it might not apply, but the risk is still not insignificant.<\/p>\n