Today for a lark I tried an open source video capture software called OBS Studio. It is available for free on Sourceforge and works on Windows, Linux, and that other one. I was pleasantly surprised to find it straight forward to use for game capture and will show you the only thing I needed to do to be up and running after installation.
Click the plus icon and add the source - in this case Steam. After that simply start recording and when you finish you'll have the base video for editing. I used OpenShot available for free here.
After adding the base video and a title card I exported in 1080 at 60fps - there were plenty of other options but this was just to test the result on YouTube.
I'll do further testing for 4K etc but needless to say I wasn't disappointed. The system impact was minimal, the quality is acceptable and the price was of course free - unless we count the $4 I paid on Steam for this game which was absolutely reasonable. I'd highly recommend both of these open source software selections for entry level video capture and possibly even intermediate video work.
4.5 out of 5 stars OBS Studio
4.5 out of 5 stars OpenShot Video Editor