Hi Guys, Just a quick question... the differerence between DDR 1,2 and 3.... in terms of pin placement on the motherboard? and am i correct in saying there is no motherboard that supports 2 different types of RAM? also... i wanted to find out the different speeds of RAM eg: 400MHZ,660MHZ 1333MHZ etc.. does that change the compatibility with the motherboard? For example, DDR2 400MHZ is installed can you insert DDR2 800MHZ and it will work? and if so will it work together with the 400 or must you have the same speed with all your RAM?