Integrated Memory Controller:
In perhaps the biggest change to the CPU's design, Core i7 processors feature an on-die, triple channel, DDR3 memory controller that support three channels of DDR3 memory per socket, with up to the three DIMMs per channel. The memory controller for Intel's previous desktop processors was always integrated into the Northbridge chip, which is part of the core logic chipset. By moving the memory controller on die, and increasing the number of channels, Core i7 processors offer significantly more bandwidth than their predecessors and lower latency as well.

Quick Path Interconnect:
Moving the memory controller on-die, also allowed Intel to design a new serial interconnect that resides between the CPU and chipset, dubbed QPI (Quick Path Interconnect). And with the memory controller on-die, that also means there is no more traditional front side bus. QPI is a serial point-to-point interconnect that offers up to 25.6GB/s of bandwidth per port over 40 data lanes--20 in each direction.