so I started reading a lot about undervolting etc. and tried it myself. I use a lenovo yoga 920 and I dont do any hard workloads, but the fan noises annoyed me as lenovo is known for its loud fans. I wanted to do smth about the noise and came to the conclusion that undervolting could help to decrease the cpu's power use and therefore the noise of the fans. I use Intel XTU and did a few stress tests with undervolting up to -0.100V. Now my laptop runs at a core package temperature of 45C on average and max is 90C during the stress test. My problem is that, just now the fans totally stopped making noise even when the cpu is under heavy demand. When i did a stress test the temp. of the cpu went up to 93C but i couldn't hear any fan noise. Just yesterday I could still hear it. Are my fans damaged? is that even a possible result from undervolting? How can I check if the fans still work (speedfan doesn't work as it does not support new laptop models) and what should I do next?

thanks in advance!

  • \$\begingroup\$ fans are just motors with a speed information return (for temperature control/management). so it cannot be impacted or damaged by undervoltage. But negative voltage makes them turning in reverse so the speeding information is inverted ; then motherboard won't unerstand the return/information so you can get strange behaviors. \$\endgroup\$ – francois P Mar 31 '20 at 17:03
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    \$\begingroup\$ So do you know what undervolting means? If you undervolt the CPU with a control program, how and why would it affect the fans in any way, unless you changed fan settings. \$\endgroup\$ – Justme Mar 31 '20 at 17:36
  • \$\begingroup\$ I just opened the back cover and ran a 5min stress test and the fans are not moving.. somebody got a clue what to do now? \$\endgroup\$ – Elias Wellems Mar 31 '20 at 17:37
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    \$\begingroup\$ @francoisP - virtually all of these types of fans use brushless DC motors with electronic controls - reversing the voltage could destroy them, not make them turn in reverse. If you need to reverse them many fans can be flipped. \$\endgroup\$ – Kevin White Mar 31 '20 at 17:38
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    \$\begingroup\$ @francoisP in any case the fan voltage isn't being changed here, the CPU core voltage is being lowered by 0.1V. Nothing is being reversed, no negative voltages are being applied. \$\endgroup\$ – Tom Carpenter Mar 31 '20 at 17:59

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