Hi all, i hope you can help me, or at least point me to some new ideas.

Subprojects: The Riesel Problem LLR and other which allow to run one WU on all CPU cores at once. Set to 8 cores (HT on, simulate 8 cores).

My i9 9900k causes some high pitched noises when i run Primgrid on it.
I've been testing on two AsRock Z390 Tachi Ultimate and one MSI Z390 Carbon. I also have now the third i9 9900k (all P0 revision). I've tested with GPU and without, tried several PSUs, even very old ones, as well. Always the same noise. Watercooling (AIO) or aircooling makes no difference.

The only change of the noise was, when i changed the memory frequency.

The CPU runs quiet except when i run Primegrid. The CPU draws around 180W all at stock in the Bios. Prime95 draws up to 200W but all quiet.

I am in contact with Intel, again, because i sen't the first CPU to them. Now with the third CPU i've gone though all the first level support stuff again, and no answer for a week now. I've been asking for a R0 Revision CPU.

All my other Intel CPUs run well with the same setup. (4790k, 5665C, 3960X, 2600K...)

I am having the problem for half a year now, and i've no idea what else i could try.

My current hypothesis is, that the soldered heatspreader might act as an amplifier. But i won't delid any 9900k just to test it. If someone has a delidded one, it would be nice to test with it.

I have made 2 videos with the noise. But you have to watch them to the end (around 40 seconds each). At the end you hear the variations of the noises.

Dropbox links:

https://www.dropbox.com/s/99j5lrcjc7yicy3/20190528_194737.mp4?dl=0

https://www.dropbox.com/s/a6ipb7l0jvjoo77/20190528_194548.mp4?dl=0

List of what i tired so far:

- Three i9 9900k
-Onboard GPU, different PCI-E GPUs
-at least three different PSUs
-two AsRock and one MSI mainboards
-AIO Watercooling, Aircooling
-different Memory (noise changes with memory speed)

If the cpu is under load, you can even hear a difference in the noise when you move windows on the desktop around.

If some else has a 9900k i hope this person could help me to repoduce the problem

My i9 9900k causes some high pitched noises when i run Primgrid on it.

That shrill sound is known as coil whine, which is a phenomenon that can occur in an array of PC components, but it typically occurs when you start up an especially taxing program. [...] Coil whine, also known as electromagnetically excited acoustic noise and vibration or audible magnetic noise, is one of the most frustrating phenomena in modern technology. As its name suggests, this high-pitched noise is caused by electromagnetic coils that act as inductors or transformers.

If it is coil whine then why does it not change when i use a Mainboard with a totally different VRM setup or a different PSU. The sound changes when i change the Memory Frequency.

Does anyone of you have a 9900k, so we could reproduce the problem i have?

And it is pretty damn loud for coil whine as well.

The sound will also change when you change project type. Useful for when you want to monitor what your PC's doing & an hear it but not see it. Tip: try AP :D.

I bought the 9900k especially for Primegrid. And as far as i have seen i get the sound as soon as i run one workunit at all 8 cores. No matter the subproject, if it supports multithreading.
I am very curious about the new Ryzens. The way it looks they should be comparable in AVX performance to the Intel CPUs. If that is true, i will try to get rid of the 9900k.

Still nobody with a 9900k?

AP is for GPUs, so no very helpful for the CPU ;)

I still believe that there is nothing you should worry about. If all components are working correctly, it is probably coil whine and it could be coming from the CPU itself.

Happy crunching :D

AP is for GPUs, so no very helpful for the CPU ;)

I have a 9900k too, in a Gigabyte Z390 Aorus Ultra board. Runs fine, quiet as can be. I've had it on a number of projects, but mostly.......

It's running without a case