Two Chip Design
Not too long ago the move from the traditional three chip setup for computers was starting. The idea was (and is) to reduce the number of parts needed to have a fully functional system. Strangely enough the original push for this was pioneered by AMD. However, for some reason AMD never really pushed forward on this. They talked up the virtues of having the functions of the GPU moved to the CPU and even moved the memory controller onto the CPU way ahead of Intel but sort of stopped there. Well with Lynnfield and the P55 we start to see some of this happening. Nehalem brought the memory controller to the CPU and Lynnfield has brought a PCI-e controller there as well.
As you can see in the CPU diagram above there is a fully functional x16 PCI-e controller. This is capable of running up to two GPUs at x8 each and talks to the board through the use of the new Flexible Display Interface (FDI) and this is the precursor to having a GPU directly on the CPU.
Also with the P55 you see the I/O controller integrated with the Clock Buffer, and Display "head end". This significantly reduces the amount of real estate needed on the board.
This should also reduce overall power consumption and heat produced by the components on the motherboard.
But just because the graphics PCI-e have been pulled off of the board does not mean that the P55 is crippled. There are still eight PCI-e 2.0 x1 lanes for use, six available ports for SATA 3GB/s, 14 USB 2.0 ports (complete with USB 2.0 hub), and Intel High-Def audio.