Surface Pro 4, annoying noise from the back!

Never done that with my two m3 when adjusting brightness

You could tell the electrical noise was related to the backlight because the pitch of the noise changed when the display brightness went up and down

The backlight noise is a defect and should be returned.

Its different than electrical noise via CPU.

When the processor is idle or performing light tasks, the down-stepping of the CPU v-core creates a slight electrical buzz. You can tell it is the CPU by giving the processor a significant load (running prime95 for example) and hearing how the pitch of the noise changes.There is nothing you can do about this noise. Some units will be better than others because of the manufacturing process, but I suspect none are perfect.

I also suspect the M3 is worse because it has no fan, and it operates on even lower voltages than the i5. I would make sure what you are hearing is cpu noise and not backlight noise though--the backlight noise is a defect and should be returned as I said.

The varying high pitch noise you are hearing - especially with the m3 because of its total absence of mechanical noise source from the inside - are originating from the CPU/chipset and likely associated with the power state changes.

If you watch closely, the pitch vary according to the activity - scrolling, touching the screen and so on.

Interesting.  When I scroll, I hear some scratchy type noise - I don't have much of a problem with this, though, because it is like white noise / fan noise which doesn't hurt my ears.  However, from the limited scroll testing I just did, the high-pitched whine didn't change much - or at least it did not change as much as it does when I change the brightness from 100% to 75%.  If the brightness is at 0% or 100%, the high-pitched noise is essentially gone.  Anything in between this, and it hurts my ears.

The varying high pitch noise you are hearing - especially with the m3 because of its total absence of mechanical noise source from the inside - are originating from the CPU/chipset and likely associated with the power state changes.

If you watch closely, the pitch vary according to the activity - scrolling, touching the screen and so on.

Hello,

I've had 3 units. The first one definitely had the clicking noise you described, I believe it was the fan controller not having a sufficiently large hysteresis (so it was turning on and off quickly). All units have the high pitch noise, yeah it can be a little annoying.

As for the high pitch noise, this is almost certainly a switching convertors wine. This cannot be fixed if this is the case, it is because of a few reasons but I'd say the inductor that is used in the convertor isn't potted in resin and its wires are what is moving.

The other possibility is that there is a ferromagnetic shield above the convertor (not unlikely) and the shield itself is being vibrated by the changing magnetic field through the switching convertors inductors.

Thank you for adding your thoughts on this issue too!  :-D

What's weird is that I never had this high-pitched noise/whine issue with my SP3. Only with the SP4.  And for me, the noise I'm hearing for the SP4s is more of a high-pitched whine, not so much a clicking noise.  Also, I hear the whine at multiple points around the device, though it's most loud near the camera sensor.

Do you think this is an issue with the Intel Skylake components, or something else?  I'd say that's one of the biggest changes from SP3 to SP4

Hello,

I've had 3 units. The first one definitely had the clicking noise you described, I believe it was the fan controller not having a sufficiently large hysteresis (so it was turning on and off quickly). All units have the high pitch noise, yeah it can be a little annoying.

As for the high pitch noise, this is almost certainly a switching convertors wine. This cannot be fixed if this is the case, it is because of a few reasons but I'd say the inductor that is used in the convertor isn't potted in resin and its wires are what is moving.

The other possibility is that there is a ferromagnetic shield above the convertor (not unlikely) and the shield itself is being vibrated by the changing magnetic field through the switching convertors inductors.