I am still a bit confused about this even after reading RAM 101-My current mobo supports DDR2 533 (PC2 4200), and I have one gig of it. If I were to get another mobo that supported a higher speed, say DDR2 667 (PC2 5300) and I got a gig of that type of memory, would I be able to combine the two speeds on the new mobo to get 2 gigs of ram at different speeds?