XFX 8300 motherboard and graphics

i have a XFX 8300 motherboard, i have put an ATI 4670 onto it. I can't play command and conquer 3 it tells me that my card does not reach the minimum requirements, it is 1GB. Apart from that i think the integrated gpu is 64mb. Command and conquer 3 requires 128mb of graphics memory. But i have been playing games like far cry 1 on the discrete ati 4670 graphics card and they have worked, maybe since Far Cry requires 64mb of memory minimum and that is accpeted by the integrated GPU. Can i only play games that my motherboard's GPU has the memory to play them as well. Regardless to my descrete graphics card? i have tried to disable the integrated graphics and i have, but command and conquer 3 keeps giving me the error that i have to make sure the graphics accelerator isn't disabled in control panel, and the graphics doesn't reach the minimum requirements.

Oh yeah, the integrated graphics shouldn't have any bearing on the fitness of your machine to play games, that's why I suspect that something is wrong with your HD4670. (most likely a driver issue)