As far as recording goes you can record at 1080p60fs around 50mbps with no problem. If you record though make sure to use the nvenc encoder, Nvidia's encoder, as it's made to use parts of your GPU that aren't being used when gaming to maximize the performance when recording. I recently upgraded to an i7 8700k from an i5 6500 and I could handle 1080p60fps on my CPU, but it was iffy at times. I'd use your GPU as there's no difference in video quality when recording and I actually prefer to use Shadowplay when recording over OBS so it primarily uses my GPU.