My current laptop has 3GB (1x2GB, 1x1GB) of DDR2 RAM installed, and they run at 667MHz. I just ordered a new laptop, that comes with 2GB (2x1GB) of DDR3 RAM that runs at 1066MHz. Is there any compatibility with the two? Can I install the 2GB stick in my old laptop in the new laptop, and have both DDR2/DDR3 and 667MHz/1066MHz operating together? Or should I buy a new RAM stick for my new laptop?