If you have an Nvidia GPU, you record using Nvidia's Geforce Experience. You can record live or press a key and it will save the last 20 minutes played.
I also stream to Twitch this way.
In fact, I'll probably make vids from Twitch streams. I've been testing some settings today, to get the best quality.
To stream 1080p at 60fps, a bitrate of 4.5 - 6 Mbps is apparently the sweet spot for Twitch, so I have adjusted mine today. I'm still using my Astros solely for the PS4 but I'm thinking of using them on the PC now, just for better quality sound and mic.
I've been streaming a little bit of the Call of Chernobyl mod for S.T.A.L.K.E.R. at lunchtime and I've fallen back in love with the game. I may do some more streaming and then use the footage for a youtube vid.
@Diddums you are one of those guys who is a natural and you need to get back to talking over vidya games on YouTube. Srsly. I was watching one of your old DayZ mod vids recently, pure quality