Intel DDR2/3 boards are not that great

An Intel engineer that really knows his way in the chipset market has confirmed that combo boards with DDR2 and DDR3 are not such a great solution. The reason is quite simple as you cannot correctly and optimally wire the board for both DDR2 and DDR3. The pathways are simply different.

This means that Combo boards will be limited in overclocking at least when it comes to memory but the same source agrees that this is the easiest way for a motherboard company to offer the easy transition.