ShadowPlay never worked on laptop cards, until a few updates ago (or so they claim). I have a GTX870M on this laptop and it won't work on this, never has. I believe it still doesn't work on laptops regardless of what they say! It works fine on my desktop, however, which has a lower spec card. It is a GREAT utility. I just wish they would make it TRULY work on laptops!!!
EDIT: I last looked when that particular update came out, and ShadowPlay didn't work. At the time, if you were running Vista or Win 7, you needed to disable Aero. There were no solutions for 8. I am going to do a little research now and see what I can find. CamStudio works, but video is comparatively poor quality. Stay tuned!
MAME Cab PC: i7 4770@3.4Ghz (passmark 9945), 12GB RAM, Win 8.1/64, GeForce GTX645 (passmark 1898); Shiny new laptop: i7 4800MQ@2.7Ghz (passmark 8586), 16GB RAM, Win 8.1/64, GeForce GTX870M (passmark 3598); Old laptop: i5@2.3Ghz, 8GB RAM, Win 7/64, Intel 3000 graphics