Weird battery and throttling bug with UX490UA (Zenbook 3 Deluxe)

Discussion in 'Asus' started by aqd, Dec 1, 2018.

  1. aqd

    aqd Notebook Enthusiast

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    Bought a refitted UX490A with i7-8550U, perfectly fine for two months but all of sudden (after charger plugged in for more than a week) the speed was reduced to 400MHz, can't go up no matter what I do, even for benchmarks. And random sleeping on Windows 10 until I removed ASUS ATK program - I saw in event log sleeping was triggered by "application interface", apparently not a system function.

    The speed issue affected both of Windows 10 and Ubuntu 18.04 - tried all CPU governors and changing min frequency as well. In event log I saw "The speed of processor 7 in group 0 is being limited by system firmware" at every boot. And charging always stopped at 50%.

    Then I let the laptop to discharge to 12% and shut down automatically. Boot again, speed is now restored, still charging. o_O

    If it's not caused by new Intel microcode, it has to be a bug or some setting in BIOS related to battery/charging, that made the laptop to think the battery level was too critical for any speed above 400MHz, but then it can't explain why charger was unable to go beyond 50%. Anyone has any idea how to find out such setting in firmware, or alternative/custom BIOS?
     
  2. aqd

    aqd Notebook Enthusiast

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    Reflashed same version of BIOS, no apparent effect.

    But then I was able charge from 6% to 100% while powered down. Maybe Windows and Ubuntu were affecting charge somehow?

    Everything is normal again, for now. :confused:
     
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