Try MSI Afterburner. Great low-resource-hogging recorder. Although it's not entirely a video recorder. So it's a little complicated to use.
It's not THAT complicated to use. But it is by far the best video recorder I've ever tried. With OBS, I was able to record HAWKEN on Ultra settings at a 1080p (but with only ~50% quality). Gameplay was about 20FPS, footage about 15.
Then I tried MSI Afterburner. Same game, same game settings. 1080p, 85% quality, gameplay affected very little, and 30FPS video capture.
Get MSI. Do it.