The Quad Core Intel Nehalem Lynnfield
The Lynnfield will be the first mainstream Nehalem, following on the successful launch (if disappointing sales) of the enthusiast Core i7 line. Lynnfield is likely to come to market as Core i5, much as Bloomsfield was the codename for Core i7 before the official name was revealed. Like Core i7, Core i5 will be 45nm, have 4 cores, and Hyper Threading, so each core can handle two processing threads. It will also have the same cache design as Core i7, featuring 8MB of shared L3 memory.
The Core i5, again like the i7, has an integrated DDR3 memory controller, but the Lynnfield’s is dual channel instead of triple channel. Unlike Core i7, Lynnfield communicates directly with PCI-e 2.0 graphics, though at a maximum of x16 lanes, which requires splitting them x8/x8 in multiple video card setups.
As the CPU can talk directly to memory and graphics, the northbridge is absent from the Ibex Peak platform on which the Lynnfields will sit. The CPU will use an LGA 1156 socket, not the LGA 1336 used by the Core i7/X58. It communicates with the Series 5 chipset, which is essentially down to providing southbridge functions.
Since the communication between the CPU and chipset doesn’t include graphics, Lynnfield and Ibex Peak won’t include the Quick Path Interconnect found on Core i7. The 2 GB/s Direct Media Interface, currently used to connect north and south bridges on the X-58 and Core 2 Series 4 platforms, will be used instead. We’ll have to wait and see if DMI is up to the new Nehalem’s demands.