Typically whether the video card
is ATI, Nvidia or Intel the drivers are modified by the laptop vendor. Meaning that Sony may modify the driver they recieve from the graphics card manufacturer. Sometimes you can get an upgrade from ATI, Nvidia or Intel and it does work but neither the laptop nor the the GP makers will guarantee success. Driver updates are more for fixing issues then improving performance. So it's allways best to look at the laptop maker's driver site first when updating drivers.