If your profile is right and you have a 750mhz G4 then NO!!!!!!!!!!!!!!!!!!!!! altho i never heard of a 750 G4. Only the Mirror Double Door (last 2 generations of PM G4) accept DDR. All other powermacs require standard sd-ram and there is no way to change it. The dual 867 used pc2100 and all others used pc2700 i belive in the MDD powermacs.