Newbie question here... I noticed that Intel 500-series chipset boards accept both 10-series and 11-series CPUs. But Intel's previous 400-series chipset LGA boards only support 10-series CPUs. No BIOS update available to upgrade. Both boards/CPUs are the same LGA 1200 socket. Why is it always necessary to buy a new motherboard when Intel makes a new CPU line? Purely a profit thing, or is there some technical reason?