okay, i know dual-ddr can be accomplished with 2 equal sticks of memory. but what happens if there is... 1 - one 256mb and one 512mb? will it be dual-ddr 512mb total? or no dual-ddr at 768mb? 2 - two 256mb and one 512mb? can the two 256mb be treated as one stick, giving 1gb of dual-ddr? curious.