The H55 Express Southbridge connects to the processor over two physical interfaces. DMI or Intel's Direct Media Interface offers serial connectivity to CPU resources for things like SATA, USB and PCI Express interfaces, while Intel's FDI or Flexible Display Interface offers connectivity to the graphics core for HDMI, DVI and DisplayPort interfaces. In addition to it's dual channel DDR3 memory interface, as we mentioned, the processor also has 16 lanes of PCI Express Gen2 connectivity for discrete graphics. This design approach will allow dynamically switchable solutions to be built with third party GPUs from the likes of NVIDIA and AMD.
Left: Intel's Core i5 Arrandale CPU - Right: Intel H55 Express Southbridge Chip
What's perhaps most impressive is the completeness of the feature set that this new Intel notebook architecture offers. From HDMI to eSATA, HD Audio, Gigabit Ethernet and DDR3 system memory, there really isn't much left out of the rather simplistic two-chip, three-die solution, save for perhaps a SATA 6G interface. Though it's arguable that notebooks wouldn't be better served moving to an SSD solution for the higher-end, especially when you consider the physical robustness they offer versus spinning hard disks.
Moving forward, we'd expect that Intel will execute on its traditional "tick/tock" integration strategy and consolidate the functionality of the Arrandale dual-die set into a single, monolithic device. Known now only as Sandybridge, Intel's 32nm technology will afford them the ability to conjoin both CPU and GPU together on the same wafer, rather than just packaging them up, which will bring intrinsic gains in performance due to a tighter coupling of the functional blocks.
Speaking of which, let's drop down a level to Intel's new HD Graphics block next.