Samsung 350V5C with AMD Radeon 7670M = problem

Hi
I bought Samsung 350V5C with Intel Core i5-3210, 6 GB Ram and AMD Radeon 7670M 2 GB running latest Windows 8

All the games that I have tried seem to be using Intel HD 4000 graphics instead of 1GB AMD Radeon 7670M. I have also assigned High Performance (via switchable graphics) to the games, but they still run using the Intel HD 4000 graphics.
*img198.imageshack.us/img198/4238/amdh.png

is there any way I can switch it or turm off integrated Intel HD4000 ??