Ed96win

Take a look at this:
 
https://www.pantz.org/software/tcpip/subnetchart.html

Take a look at this:
 
https://www.pantz.org/software/tcpip/subnetchart.html

Maybe some old HDMI ports don't have enough power through it .. that's my theory.

Why are you using an old monitor with an RX580? You could've almost buy a new monitor for the price of the adapter... 

the usb port is there for power as this is an active converter.

The micro USB port might be there for some active conversion. I don't know what it does on your adapter though, you didn't mention a product name.

VGA doesn't carry audio, presumably the micro-USB is there to carry the audio.

Ok, well from experience getting properly cooled case will drop temps some (from bad airflow to amazing airflow up to 5C). But getting better CPU cooler or dropping overclock will do much more.

You are overclocking with stock cooler. Temps are probably somewhat expected. Whats your room temp? Have you tried having one intake and one exhaust instead of two exhausts?

If you plan on pairing it with anything above a Ryzen 3600, then I would advise against the B450-F from ASUS as its VRM cooling is very poor and could cause reliability issues in the future, as you can see here. Instead, I would suggest a B450 Tomahawk Max from MSI.

What form factor? If you case supports ATX I'd recommend ASUS ROG STRIX B450-F Gaming

Personally I'd switch the two fans you have (or at least one of them) to intake, but honestly it doesn't sound like you even have a problem. It's a gaming rig, not a cinebench r20 rig. If it doesn't reach 50 when doing what you intend to do with it, the cooling is fine

The CPU won't be operating as an APU if you're not hooking display elements into it. So that won't be an issue.

nope, 8X PCIe 3.0 is plenty for just about any graphics card.

Start by getting an RX 580, see what performance increase that yields for you. I bet it would suffice as the whole upgrade

I have to agree with the above statement. Your 2400G is a multithreaded 4 core CPU. 8 threads is plenty for gaming, and you're not getting much if any speed increase by buying a 2600, just getting two more cores. 
 
Get a cooler you like if you want to overclock,  but you really wont see a ton of benefit in gaming. Maybe the MA410P or MA620P for RGB if they are in am affordable price range. 
 
The thing that will make a huge difference in gaming is adding a discreet GPU. I agree with the recommendation for an RX 580 if your gaming is light. Though I'm unaware of any with RGB lighting, note that the cooler face of the card is not visible in almost all cases. All you see of the card is the side plate and the top, which looks like the backside of a circuit board. So I would grab a SAPPHIRE cooler for the good cooling, and not worry about the look. 

Just adding an RX 570/580 to a 2400G system should already make Apex Legends plenty playable, but make sure the PSU is at least acceptable.
 
Deepcool Gammaxx GT is probably the best budget RGB cooler, Hyper 212 except the Black and Black RGB all use bad X-shaped mounting frame which is really hard to install.
 
not that the Gigabyte card is all that good anyway

Motherboard voltage readings aren't perfectly accurate. You're never going to see perfect 12.00V, 5.00V, 3.33V. Those values are all perfectly reasonable and within expected range.
 
Glad to hear that a new unit fixed the coil whine.

Just stick to like 1400mhz, your RAM's speed/timings matter a lot more for the iGPU's performance.

Coil whine itself is essentially harmless. The only problem it causes is the high pitched whining you have to listen to. You'll have to decide whether or not you can tolerate the noise or if you want to return it and swap it for a different unit.

It will be fine. Its not a great PSU, so if you ever decide to put more into your system (as in a moderatly powerhungry GPU) id suggest swapping

Its not a good PSU. So coilwhine isnt exactly suprising. 
 
Might want to look at a bequiet pure power 10/11 400w. Tho some coilwine is allways liveable.

From what you have described here, it is most likely what is known as "Coil Whine".
 
Is it definitely coming from the PSU and not something else, such as the motherboard (in particular around the CPU area)?
If it's the PSU and the replacement PSU is also giving you the problem then send it back again and complain to Cooler Master. Or if you can get a refund on the unit and buy something else.
 
No. Your system without a graphics card will consume less than 100W under load.

sounds like coil whine
 

new gtx1660/ti
or used rx 570