i dont have one myself as currrently running an all AMD 750 chipset board, though im also looking at the A7M266 for my new build soon. I believe your second statement is correct, to install the AMD AMG Miniport driver, and the select via drivers, basically make em '3in1'
EDIT: WTF, thats one hell of a typo there, AMG slot? LOL....AGP Miniport driver is what i think i meant, hehehe
