What Sony computer do you have and which operating system.
I would recommend getting the drivers from:
http://www.amd.com/us/Pages/AMDHomePage.aspx
on the top right hand side of the screen is a pulldown menu "Find a Driver" and you can then select if its a laptop or desktop graphics card, your Operating System and 32 or 64 bit etc.
Usually companies like Sony will use the driver from AMD/ATI or Nvidia and then customize it for their machines, but these drivers do not come out as frequently as they do from AMD or Nvidia