hi, im new to mac. i need a ultra mobile and powerful system so people said by a power book. i went looking and likes the 15inch. here is how i would configure it. 1.67 G4 1.5GB of ram ATI 9700 with 128 VRam 80gb hard drive Combo drive Do i have what is required to play doom 3 at the maximum resolution the screen on the power book offers at medium settings with the shadows turned off well? please i am planning on making my perchase soon and i need to know this.