Whilst I agree that more threads 'could' help gaming + streaming on one rig, the GN video was stupid, he ran it in software mode, which pretty much no streamer does. I have streamed e.g. at 60fps just fine using my 8600k and was a cpu demanding game but of course I had OBSS in gpu mode not software mode, why GN did that I have concluded was simply to market the AMD chip as best as he could. The video was stupid.
Also if going ryzen the 2600 seems the best buy of the bunch in my view, probably 95+% gaming performance of a 2700x for a noticeably lower cost.
Software encoding is on the CPU, of course he used that because the CPU is what he was testing.. Hardware encoding is off the GPU or an iGPU.. where the quality is horribly reduced and looks terrible when using the same bitrates and profiles etc.
For me the 2700X is a no brainer for streaming with a single PC setup, i can do 720p60fps, 6000kbps, Medium preset/Main profile with ease.. barely goes over 50-60% CPU usage, and that includes streaming Arma 3 aswell. That gets even lower when using Fast preset/High profile or Faster preset. Just whack a decent cooler over that CPU that is going to be encoding for a prolonged period of time and you're good to go.
If someone is serious about streaming while gaming, to the point CPU resources are serious consideration, they'd be better off going to an external capture card and an additional machine for compositions/encoding though obviously not everyone has the budget and/or do it often enough to be worth setting that up.
Unless you have cash to throw away, streamers dont usually get a second streaming PC setup until they have earned enough from streaming to afford it. I had a 2 PC setup for a couple of months, 6700K gaming and 2700X streaming.. as good as it was, audio setup can be a real issue, updates from Microsoft, audio or your capture card can mess things up every time.. it can become a ballache, i see streamers on Twitch complain about it a lot.
AMD has made streaming a lot easier on a budget build, only question is which way do you go?
If you have the cash then go Intel (Sacriel has a single PC setup, 7900X), but most people that start streaming and want to do it for the money, cant afford a 2 PC setup in the first place.
AMD will be the more affordable way to get their streaming career off the ground, and if it doesnt work out as you would have liked it to go, then you didnt spend all that cash on a stream PC for nothing