In the case of the nVidia presentation, it's quite obvious from the video where it's CGI Ceo: Awkward standing position, stiff arms and fairly inarticulate fing

In the case of the nVidia presentation, it's quite obvious from the video where it's CGI Ceo: Awkward standing position, stiff arms and fairly inarticulate fingers. He looks fairly suspended, as if there's nothing to convey weight/physics in his movements... however brief.