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Old 04-20-2019, 11:00 PM
Cherry7 Cherry7 is offline
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Default Fan speed reads at 5000 rpm even though there is no fan at all


tldr: my cpu "fan" reading says ~4000-6000 rpm even though in reality there are zero fans attached to the motherboard. Everything is either through H100i's iCue or NZXT CAM, both through USB 2.0 to the motherboard.


I just built a new rig in March 2019. Here are my relevant specs:
ASUS Prime x470 Pro
H100i Platinum SE
NZXT H700i with 3 front 120 mm fans (The rear 140mm fan was removed).

My CPU fan reading (on HWMonitor, NZXT CAM, and ASUS BIOS) reads around 4000-6000 RPM. However, in reality, I do not have a single fan (of any kind) connected to my mother board. I have the two 120 mm LL fans from corsair for my H100i for my cpu. But those are both attached to my H100i directly through USB (basically whatever the Corsair install directions said). My NZXT fans are run through the CAM hub, but the CAM hub is connected to my motherboard through USB as well. Thus, there shouldn't be a single fan connected to my motherboard. Yet my "cpu fan reading" still says 5000 rpm. My actual cpu radiator fans, run through iCue is working just fine. So are my other fans. Even if I assessed this setup wrong, there still isn't a single fan running at all times (idle or load) at 4000-6000 rpm. That "phantom" fan doesn't exist.

Just wondering what is going on with that reading? Have I assessed this right?

I really just want to know where this "phantom" fan reading is coming from. And how I can get rid of that reading? Should I instead connect a fan to the motherboard itself? Nothing is actually wrong with my system. And clearly there is nothing running at 5000 rpm. Thanks!

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Old 04-20-2019, 11:57 PM
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DevBiker DevBiker is offline
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That fan reading will be from the H100 if you installed it as per the instructions (with the fan header to the CPU_FAN header). This provides a fan tach signal to the motherboard so that you don't get a CPU_FAN warning on boot. It also serves as a fail-safe as you'll get that warning if your pump fails.
Please click "Edit System Specs" and fill out your system info.

This comment is provided "as-is", without warranty of any kind, express or implied, including, but not limited to, the sanity or mental fitness of the author. The author is not a Corsair employee, does not represent Corsair, and no comment should be construed as an official statement from Corsair.

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fan, fan speed, speed

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