David had said that his games were failing – all running slow. I stopped in after work and disabled the On-board Gfx card. He also had to change a setting in a game ‘settings’ file back to the way it was previously, as he had made a change to try and force the game to use the NVidia card – which obviously did not work.
Anyhow, all was well on leaving with a high frame rate and no jerking.