So after almost 2 weeks now I started hearing strange rattling sounds coming from the left middle part of the notebook.
After reading a bit about noises from notebook parts it seems to be related to GPU coil whine. I might be wrong here but the symptoms make it likely...
I first thought it would be the HDD (as that's also almost the spot where it is) but it kept going even after deactivating it through the cmd (select volume, remove). Or wouldn't that be enough to stop the HDD from moving?

This now happens as soon as I start some more or less graphic intense programs, though it seems to be that even youtube, the steam store or hearthstone seem to be enough to make it appear.

When "hitting" gently on the part right to the left of the touchpad it sometimes seems to help with the noise.

I am already using Intel Extreme Tuning to undervolt the CPU as suggested in another thread here as well as MSI Afterburner to slightly undervolt the GPU. Changing any of these settings didn't seem to help though.

Does anyone have a similar issue and might have a fix for it? Since it's holiday season returning it now might prove difficult... and after already fixing all the other problems, this is really a bummer ^^

/edit: just looked at some pictures to see where exactly the gpu and cpu are placed. From the placement it should rather be the HDD than gpu/cpu... Also after that "gentle hit" it doesn't seem to matter whether I do any graphic intense "work" (aka gaming on ultra settings) or just browsing... it stays silent until I move the notebook around