Small FPS drops ; buzzing front panel audio

Hey there, you are basically my last hope as the support only suggested to RMA stuff I've asked this on another Forum, but no one could really help me.

Two problems:
When I shut down the PC wile leaving the PSU Button ON the pc will boot up without problems BUT when I shut down the PC AND switch the PSU to OFF it will boot for a second, RED light for CPU shows up on Mainboard (according to Manual RED = CPU), then immediately shuts down, fans stopping, and finally boots on without problems again.

Buzzing over Headphones only when plugged into the front panel.
FPS drops but only for 0,5 - 1 second and sometimes it even jumps up 1 fps resulting in stutter, too




I've had it on my old PC (which I've sent back and received the same again, so basically on 2 different systems [only the fps drops not the boot up problem)

H310M pro-m2 plus
i5 8600
GTX 1070
Noname 500w PSU - happened on both, the one I sent back and the replacement.


Then I've upgraded to the following

ROG Strix 390-E
I7 8700k
GTX 1070
Seasonic Focus 650W Platinum



What I tried:

Watching Task Manager and Process-Explorer searching for demanding tasks
Tried XMP and XMP1 Profile
Watching temperatures (Just yesterday the Temps got even better, as I've put a case fan in, it was fine before, except for the psu getting high temp because of the hot air accumulating) - so no thermal throttling
I did two userbenchmark tests (one on my old and one on this system) where everything was at least running as expected or above
Disabling V-Sync - then I'll get more fps but strange enough : I'm still experiencing stutter on my 60hz tv when the fps drop from 100fps or higher to 95-97fps (I just don't get it)
Tried different GPU drivers, from older ones to newest, installing them using DDU - nothing
Moving Games from SSD to HDD

Changing Nvidia Power Plan to Max
Changing Powersaving option to high performance
lowering graphis, setting high resolution and high settings to see if anything changes, but nope.

I'v also bought something to test the socket's grounding, should arrive in an hour.
RAM and CPU are dropping from their max boost kinda fluctuating
Ram = from 1333 to 1332MHZ
CPU from 4400 MHZ to 4397MHZ (sometimes a bit more or less, for both RAM and CPU)
Should stay constant while ingame right?
The highest my CPU consumed inside a Game was 45w, most of the time it sits at ~30-35w while on turbo-boost




Pleas help me Guys

Why can't I edit? I can't find it, but I've got to tell you this:
The Testing-device just arrived and everywhere it shows "HOT/Neu REV"?

Edit: Forget it, it is indeed "HOT/NEU REV" for most outlets but my multi-socket surge protector is indeed grounded, so that is confusing me even more, why the buzzing? is it still dangerous/harming?

I probably need to calm down

Thanks for the reply, Guys.

So the buzzing is gone now and the device only detected grounding when plugging it in the other side around (the head facing you, cable going away from you, kinda hard to explain with my underdeveloped english skills xD).

And just to be extra sure I've checked if the frontpanel cable is connected properly.
Now there are no more Bootup problems when I've completely shut down my pc and turn the powerswitch to off.

though, now I'm hearing some kind of electrical noise every now and then, can't tell where they come from as they occur randomly and only for a second, sounds similar to when I shut down the PC then there's a kinda click sound (and I ruled the Fans out)

But the FPS problem still persists and it seems to be a timing problem (ms), @60hz and full hd it shows 58/59 fps while timed at 16,9 to 17,0 ms)
I'm using a HDMI cable from my ps4 could that be a problem too?
Should I open a new thread as it seems to be TV-related.