Sucks to be you then. Or your ISP sucks. If your ping went up and down-/upload went down after streaming they might be throttling you.

Which speedtest site did you use by the way? ISPs tend to unthrottle the most common ones so if you use a more obscure one chances are you'll see what speed they're really giving you.
https://speedof.me/ might work.

Yes, but is this a "pay for 5, get 2"-situation? If the connection can't do more the latency will go up at high load.

Well there is a difference between "2 Mbps because that's what you paid for, it could do 5" and "pay for 5, get 2" or "we're selling this as 2 Mbps because it gets 2 once in a blue moon".
I'm guessing you're in of the later categories.
What does a speedtest say?

Assuming it's not your CPU being garbage and choking on the encoding.

Yes, that should be good.

Well it's about power delivery. Any mobo is fine when the CPU draws 100W, but when you overclock it and it draws 150-200W the bare minimum isn't enough anymore.
https://www.overclock.net/forum/attachment.php?attachmentid=99753
https://www.overclock.net/forum/attachment.php?attachmentid=231464
You don't need anything crazy, just not in the red. Even yellow is fine.

I mean if you're buying from different shops you can afford it anyway, so there's no use in cheaping out and getting a lower overclock after you've paid >80€ more for a Z mobo and cooler.

The main difference will be the cooler, you'll have to check reviews to see which one stays cooler (or actually boosts higher at the same temperatures) or which one is quieter.

Yes, but either go all the way down to the Z370-A PRO (pretty much no difference to the Z370-P) or get a mobo with good VRMs.

In all games other than TF2 the 8350K should be more than enough.
https://www.techspot.com/review/1006-the-witcher-3-benchmarks/page5.html
8350K ~ 4690K
Even underclocking the 4790K to 2.5 GHz doesn't change anything. That's on medium with a 980, but a 1070 is nowhere near twice as fast so you're still GPU limited no matter what.

Yes, 2 fans usually mean it's not a mini version (some rare exceptions exist).

PSU should be fine.

Let's just have a look at pcpartpicker. 3600 RAM isn't going going to be much cheaper, but 3200 (with the same or better latency) is definitely cheaper outside of that shop.
https://fr.pcpartpicker.com/list/cwZcjy
This is all with equivalent or better components and on pcp, which is terrible in France because for most parts it shows only Amazon and for most where it does know other shops it's just LDLC and Alternate which aren't any cheaper and it still saves >120€.

If you invest more time and do comparisions manually or via a site you can definitely go lower.
E.g. https://www.rue-montgallet.com/prix/acheter,seagate-barracuda-1-to-st1000dm010,818138

Indeed, according to the rules of the Internet this is completely legal.

Yes, that's about what I was thinking too.

You can look in the benchmark thread to get a more accurate estimate for TF2. Take your current fps in 6s/pubs with the settings you want, run the demo and then based on the ratio you should be able to get a rough idea of you need by comparing the demo result with results in the thread.
However I believe that you'll probably have to overclock. Since you're already going for the 8350K and need a cooler anyway the only difference would be a Z370 mobo. That would also allow you to run faster RAM (TF2 loves fast RAM, especially timings are important) since B360 is limited to 2666. 3200 CL16 shouldn't cost much more, there's even one 3600 CL19 kit in stock for 167€ right now.

There are cheaper cases with two fans, the for example Focus G should work, I think, but there's probably other options as well.

The way I see it you've got 3 options:
1. Optimize for TF2. Z370/Z390 mobo and faster RAM, GTX 1060.
2. Optimize for the other games. Usually I'd recommend the 8300 so the drop isn't too much but you save 30€ and don't need a cooler but that shop doesn't even offer it and the 8100 is almost twice the price it should be so I'm not sure it's even worth it. Simply getting a cheaper case would get you back within budget so it's better to do just that.
3. Go over budget and do both. With the RAM I mentioned, the Focus G, cheaping out on the mobo (will limit your overclock a bit) and getting a 250GB SSD instead of 500B you can get it down to 1230€, which isn't too bad I guess.
Ideally you'd want to keep the 500 GB SSD (+30€) and get a mobo with decent VRMs, but that would cost you at least another 50€ in that shop.

Yes, for that CPU you'll need a cooler.
A case that simply comes with 2 fans would be nice.

Honestly you should check a few things first.

What are the "(sometimes heavy) calculation" you'll run and does it even benefit from more cores?
What clockrate do you actually need to get 200 fps in TF2 in the gamemode you want, on the settings and resolution you want to run? Then you'll know if you'd have to overclock to reach that or not.
What GPU do you actually need to get 100+ fps in all those games on the settings and resolution you want to run?

Once you figure that out you'll know if you can afford both or if you'll have to choose or lower the settings.

More cores with lower clockrate is a bad trade for games, especially TF2.
Pay those extra 5€ for the CXM450, it's a different and much better PSU.

2070 ~ 1080 and the prices have been staying similar for a while now. I don't see any reason why that would change.

No, pcp is right, but I'd recommend get a mobo with 4 RAM slots anyway so while we fix that we can spend another 10$ to get a B450 mobo instead and save you the hassle of the BIOS update if you want. If you want to save the 10$ there's always hoping that the mobo comes with a reasonable recent BIOS (it's been 6 months since the 2200G's release after all), getting the mobo from a retailer who will update it for you (if you can get it for the same price there) or this https://www.amd.com/en/support/kb/faq/pa-100 .

By the way the RAM didn't have a price last time I checked so you're actually over 600$ already, which makes it a bit more difficult, unless you weren't counting the monitor.

https://pcpartpicker.com/list/TxZ4jy
Didn't touch the monitor, other than that what I said and cheaper and faster HDD and GPU and a case that comes with 2 fans (just one option, there's others) instead of buying 2 extra.

#3116
If it's a budget build you should probably tell us the budget.

At the very least you can get a 2200G for the higher clockrate, dual channel RAM, a cheaper PSU (e.g. https://pcpartpicker.com/product/FQ648d/corsair-power-supply-cp9020101na ) and maybe both a better SSD and a better monitor.

#3120
Reassembling is the hardware equivalent of "have you tried turning it off and on again". 60% of the time it works every time. So if you try it twice it's 120% guaranteed to work.

#3122
240 fps in general or just TF2?

It should work but TF2 doesn't benefit from more than 4 cores so you could get an i3-8350K instead to save money or 8600K/9600K for the higher stock clockrates or even 8086K/9700K (nominally not much more expensive than the 8700K, but reality is different).

Ok then, it's not guaranteed but the mobo is the most likely culprit.

A used mobo would probably be cheaper but there seem to be quite a few options available.
https://pcpartpicker.com/products/motherboard/#c=110,119&sort=price&page=1
The GA-Z270P-D3 is on the low end like the Pro4, so it depends on how high you want to overclock, but other than that's it's a decent choice.
The Extreme 6, Extreme 7+ and MAXIMUS VIII RANGER (thanks for the caps ASUS) are all on sale for 100-110$ and quite good but also Z170 so you'd have to deal with the BIOS update.

Did you actually remove the motherboard from the case? That's important. Ideally do a visual inspection, check if anythings lodged in somewhere.

If you did the paperclip test properly the PSU is dead. It doesn't tell you anything about the mobo. That's the whole point of the paperclip test, to test the PSU with nothing connected to it.

So first if you didn't do it already do the paperclip test properly, with nothing connected to the PSU. Of course the PSU and mobo could both be dead but let's make sure first.

The next step is to test for shorts. If for some reason there is a short the mobo will not start and it should not start with any PSU since that would kill it. So you remove everything from the case, put the mobo on a non-conductive, smooth and flat surface (no carpet please) and try to boot with only the CPU, the cooler and the RAM installed. Of course you need a PSU that passes the paperclip test for this.
If this test fails as well then it's probably not looking good for your mobo.