Surface Pro 4, annoying noise from the back!

Thanks for the tip.

I prefer the singing crickets rather than a warm device and short battery life ;)

The two SP4 m3 in my household do present this "singing crickets" noise...

I've found a work around of sorts for these hungry singing crickets that are infesting our computers.  You need to feed the crickets a steady diet of roughly 20% CPU usage.  For example, I've been using this wxMaxima script that generates random numbers forever:

k: 1$ while k > 0 do( k: random(100) + 1 );

The crickets will stop singing as long as they have a steady diet of numbers to crunch on.  Of course they will get a little warm and munch on your battery as well...

I've noticed a very high pitched electrical noise coming from the top right side of the SP4. It seems like it's related to the backlight and battery saving mode, as when the brightness is at 100% without battery saver, the noise is gone. However, on any other brightness/power saving setting, it is present.

I can hear it clearly in quiet rooms, and it's extremely frustrating.

The two SP4 m3 in my household do present this "singing crickets" noise. They were bought a month apart and thus likely from the same hardware (chassis) revision. In both cases, the sound is obviously modulated by processor activity and has nothing to do with screen intensity.

You may be facing an issue different from mine.

But in my case, it's clear there's nothing that can be done without a replacement.

And the issue is so minor I would never take the chance of getting a tablet worse than the one I have.

Hoping your issue gets resolved to your satisfaction.

Replacing the device won't change anything.

This is a CPU/Chipset issue and likely related to the dynamic power state/clock speed variations.

Anythnig running in the background will generated this "singing crickets" noise even if you stare at your screen. A lot of people won't hear it because their environment is too noisy but a quiet room easily reveals it. The SP4 with the m3, being totally silent, may appear more affected by this curiosity.

Unless Microsoft changes the way the SP4 is built, it won't change. Either you get over it or get a refund and buy something else.

It's not just "Either you get over it or get a refund and buy something else."   You forgot a third option: Work with Microsoft to see if we can find a solution and make it better.  The Surface is an amazing device, and I would like to help make it better and work out it's wrinkles.  I have yet to find another device that does what the Surface does as well as the Surface does it.

As I've said before, the "high-pitched ear-ringing tinnitus mosquito noise" problem I have identified is completely unrelated to background processes.  The only thing I have identified that affects it is the brightness setting.  The problem has been there on first boot-up of every new Surface Pro 4 replacement I've had, and it has been there on every floor model I have observed (minus one, though I was in a noisy room).  I have not observed this problem on a Surface Pro 3.

Anyhow, I agree that it is likely a CPU/Chipset issue.  A tech support rep told me that engineers told her the issue has been identified and addressed in recent production lots.  Based on this information, I did not return my device before the return date.  However, when I went in for a replacement with a newer production lot, the problem was still there.  This was unfortunate, since I was told it would be fixed, and I spent a LOT of time and fuel on getting the replacement.  But I still think the problem can be fixed, and I hope to help.