4 ms·
You mean "Disable CPU Power Management in BIOS"? I tried that. Not sure if it made any change at all. The noise is still too much to make the laptop useful. S
by Timja 4y ago
You mean "Disable CPU Power Management in BIOS"?
I tried that. Not sure if it made any change at all. The noise is still too much to make the laptop useful.
Strangely, putting the laptop under load makes the coil whine go away. So it might be related to CPU power management somehow.
The fan speed that is also mentioned does not seem to have any role in this. The noise happens no matter if the fans run or not.
- Gibbon1 4y ago> putting the laptop under load makes the coil whine go away Probably be sub-harmonic oscillation. Under light loads the control loop can 'hunt' at a much lower frequency then the loop frequency. Combine that with an unlucky inductor and you get a high pitched whine. It's an annoying problem because in susceptible designs it'll show up in a small percentage of some but not all production lots. Take your laptop back.
- jbay808 4y ago> Strangely, putting the laptop under load makes the coil whine go away When the load is low, a switching regulator can enter "discontinuous conduction" mode, where the inductor current periodically drops to zero. This is typically noisier than continuous conduction mode, where current is mostly constant with a small sawtooth ripple.
- thijsvandien 4y agoI fairly recently bought a fanless Shuttle barebone with a modern Intel CPU, that produced unbearable coil whine. It too became silent when kept busy. What solved it was disabling C-states and P-states.