The only thing we know about you is that you mention a GTX 1080 in the title, and a 1080P resolution in the body of the post. You suggest there's low fps when recording.
List all of the hardware in the computer, and the software names and versions used. Are you saving the recordings to the same drive the game(s) are installed on? There's a ton of information missing that would help answer the question or lead to troubleshooting steps that might help you get some more fps.