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.
For those who don’t want to watch all of it (even though it is quite excelent) the points I remember are:
- subsurface scattering of skin
- do the pores stretch? (As the face is moving)
- movement, especially movement of the upper lip as the character speaks